When to fertilize boxwoods?

Fertilizer is material that is applied to the soil or sprayed on crops aboveground directly or indirectly in order to supply nutrients, increase crop yields and improve product quality. Direct fertilizer supplies essential nutrients to crops, including NPK fertilizer, compound fertilizer and micro-element fertilizer, etc. Indirect fertilizer is used for improving soil physical and chemical properties, thereby making growth condition of crops better, such as lime, gypsum and bacterial fertilizers. Fertilizer is in a variety of classification method and types, while having great difference in ingredient and chemical property. What are different types of fertilizer? How to classify the fertilizer? This question is explained in further detail below.

Inorganic fertilizer
Inorganic fertilizer or chemical fertilizer contains one or more nutrient elements for crops growth, which is made by chemical means. It includes nitrogen fertilizer, phosphate fertilizer, potash fertilizer, micronutrient fertilizer and compound fertilizer, etc. The fertilizer is characterized by simple component, high nutrients and long fatty effect.
Nitrogen fertilizers
Nitrogen fertilizers contain nitrogen that crops need during development. Nitrogen plays a very important role for crops growth, which is part of amino acids in plants and is a component constituting the protein. Meanwhile, it is constituent part of chlorophyll that tips the balance in the process of photosynthesis. Nitrogen can also help crops sub-colonization. Nitrogen fertilizer can not only increase production of agricultural products, but also improve the quality of agricultural products.

1.Ammonium nitrogen fertilizer
Ammonium nitrogen fertilizer contains ammonium bicarbonate (NH4HCO3), ammonium sulfate {(NH4) 2SO4}, ammonium chloride (NH4Cl), ammonia (NH3.H2O), ammonia (NH3) and so on. Ammonium nitrogen is easy to be adsorbed by soil colloids, partially into the clay mineral crystal layer. Ammonium nitrogen becomes nitrate easily by oxidation. Ammonia losses volatilizes in an alkaline environment. When crops absorb excess ammonium calcium, magnesium and potassium, it cuases a certain inhibiting effect. Ammonia has a strong irritating odor, corrosiveness and volatileness. Therefore, it can not be directly used for fertilizing. It is available after configured to dilute ammonia.

☆Ammonium bicarbonate
Ammonium bicarbonate is white compound and crystal in granularity, clintheriform and columnar. Aqueous solution is alkaline. Because of unstable nature, it is decomposing into carbon dioxide, ammonia and water above 36℃.Decomposition is finished at the temperature of 60℃. Nitrogen is used for a variety of soil. It can provide ammonium and carbon dioxide for crops growth. Because of low nitrogen content, it is easy to agglomerate. It not only promotes crop growth and photosynthesis, but also helps crops come into leaf.

☆Ammonium sulfate fertilizer
Ammonium sulfate fertilizer is white orthorhombic crystal, which is soluble in water and insoluble in alcohol. Ammonium sulfate is mainly used as fertilizer in agriculture. The advantage of the fertilizer is relatively small hygroscopicity, not easy to agglomerate. Compared with ammonium nitrate and ammonium bicarbonate. Ammonium sulfate has good physical properties and chemical stability. Ammonium sulfate fertilizer is readily available fertilizer and good biological fertilizer. The reaction in the soil is acidic so that the fertilizer is fit for alkaline soils and carbonaceous soils. The disadvantage is that nitrogen content is low.

☆Ammonium chloride
Ammonium chloride is white crystal or colorless crystal powder. Hygroscopicity is small, but it can absorb moisture being caking in wet rainy weather. Powdered ammonium chloride is easily deliquescent, qualified products even worse. Moisture absorption point is generally about 76%. Therefore, the fertilizer should be kept in dry place. It can be used as fertilizer. Avoid using ammonia fertilizer with alkaline fertilizer. It is better not to apply the fertilizer in saline-alkali soil as it may reduce fertility.

2.Nitrate nitrogen fertilizer
Nitrate nitrogen fertilizer includes nitrate fertilizer sodium nitrate (NaNO3), calcium nitrate {Ca (NO3) 2} and ammonium nitrate (NH4NO3), etc. Nitrate nitrogen dissolve easily in water and moves fast in soil. It not only promotes cation absorption, but also facilitates the synthesis of organic anion. For instance, corn and wheat prefer nitrate nitrogen fertilizer. Under the condition of equal nitrogen amount, yield-increasing effect of nitrate nitrogen fertilizer is more prominent than other nitrogen fertilizers. Vegetables have strong preference for nitrate nitrogen. In hydroponic experiment, as long as the nutrient solution is added nitrate, vegetables grow normally without ammonium or urea nitrogen. Simultaneously, tobacco responds to nitrate well. Applying nitrate nitrogen fertilizer increases output of tobacco and improves its quality.

☆Sodium nitrate
Sodium nitrate is colorless transparent or white rhombohedral crystal. It is easy to deliquescent. Under the condition of small amounts of sodium chloride with impurities, deliquescence of sodium nitrate would greatly increase. Sodium nitrate helps combust, so it should be stored in a cool well ventilated place. It is used as readily available fertilizer, especially pertinent in beets, radishes and so on.

☆Calcium nitrate
Calcium nitrate is a typical fast-acting foliar fertilizer. It can successfully act on acidic soil because calcium can neutralize soil acidity. It is convenient for regeneration fertilizing of winter crops, additional fertilization and excessive consumption of alfalfa growth. In addition, it is widely used for sugar beet, fodder beet, poppy and corn, supplying calcium for crops.

3.Amide nitrogen fertilizer
Urea, also known as carbamide, is a white crystal and one of the simplest organic compounds. The nitrogen content of urea is 46%, which is the highest in solid nitrogen fertilizer. It is the final product of protein metabolism in mammals and some fish. As a neutral fertilizer, urea is suitable for a variety of soil and plants. It is easy to save and use. Because of small destructive effect to soil, it is the chemical fertilizer with heavy usage. Urea is the most common nitrogen fertilizer. Urea is suitable for all crops and soils, which is used for base fertilizer and additional fertilizer.
Urea is used as base fertilizer and topdressing, sometimes as seed fertilizer. Under normal circumstances, urea conversion needs 7-10 days at the temperature of 10℃,4-5 days at 20℃, and only two days at 30℃. When urea is converted to ammonium in the soil, it can be absorbed by seedlings in quantity. Therefore, the utility of urea fertilizer should be a few days earlier than the other administration.

Phosphorus fertilizer
Phosphorus is the the main nutrient in phosphorus fertilizer. Fertilizer efficiency depends on effective phosphorus pentoxide content, soil properties, fertilizing method and crop strains, etc. Phosphorus is a component of the cell protoplasm in plants. It plays an important role in cell growth and proliferation. Phosphorus is also involved in photosynthesis, the use of sugar and starch and energy transfer. Phosphate fertilizer also promotes the growth of plant root systems, making the plant ripe early. In the fruit stage, massive phosphorus transfers to the grain, making seed full.
1.Water soluble phosphorous fertilizer
This kind of fertilizer is soluble in water, having high fertilizer efficiency.
The main products are calcium superphosphate and triple superphosphate.

☆Calcium superphosphate
Calcium superphosphate, also called ordinary superphosphate, is obtained by decomposing phosphate rock with sulfuric acid. Calcium phosphate contains effective 14% ~ 20% P2O5(of which 80% to 95% soluble in water), being a part of water-soluble phosphorous fertilizer. It is gray or white powder (or particles), which can be used as phosphatic fertilizer directly or compound fertilizer ingredients. To mix with nitrogen fertilizer is conductive to nitrogen fixation, reducing nitrogen loss.

☆Triple superphosphate
Triple superphosphate is small granular solids, slightly acidic, which has gray or dark brown colour in appearance. It is suitable for long-distance transport and storage. It is soluble in hydrochloric acid, nitric acid and water, practically insoluble in ethanol. Triple superphosphate fertilizer is suitable for a variety of soil and crops. It can be used as base fertilizer, topdressing and compound (mixed) fertilizer. It is widely used in rice, wheat, corn, sorghum, cotton, fruits and vegetables, etc.

2.Mixing soluble phosphate fertilizer
Nitrophosphate is the fertilizer that obtained by decomposition nitric acid, while N/P ratio is 2:1. The use of the fertilizer can supply trace elements in the soil. It can also significantly improve the quality of agricultural products. Nitrophosphate applies not only to wheat, corn, rice and other food crops, but also for rape, tea, cotton, garlic, banana, litchi, apple, watermelon, grapes and other industrial crops. It should be deep placement, casingsoil, deep application of base fertilizer, to avoid contacting with the seeds or roots directly. It is generally used as base fertilizer for common field crops and top application for industrial crops. It is better to apply frequent, small amounts of fertilizer, which aims to improve the utilization of fertilizer.

3.Citrate-soluble phosphatic fertilizer
This kind of fertilizer is insoluble in water. It mainly contains precipitated phosphate, steel slag phosphate fertilizer, calcium magnesium phosphate and defluorinated phosphate fertilizer. Generally, it is applicable to the acidic soil, so it should be used for base fertilizer. It can be dissolved by organic acids that are secreted by soil and plant roots , and then it is gradually absorbed by crops.
Potassium fertilizer
Potassium is the primary nutrient in potash fertilizer. Potassium in plants usually accounts for 0.2% ~ 4.1% of dry matter, second only to nitrogen. In plant growth and development, potassium is involved in the activation of more than 60 kinds of enzymes, photosynthesis, assimilate transportation, carbohydrate metabolism and protein synthesis.
1.Muriate of potash
Potassium chloride is chemically neutral and fast-acting fertilizer, which is well suited for rice, wheat, cotton, corn, sorghum and other field crops. Because of physiological acidity, potassium can be used in neutral calcareous soils. It can be used as base fertilizer or topdressing. Because potassium chloride fertilizer contains a large amounts of chloride, it will affect the growth of seed germination and seedling.
When it is used as base fertilizer, it should be applied to arable soil 10-15 days before sowing. It should be used early in order to leach chlorine ion to lower soil by rain or irrigation water, removing or reducing damage to crops.
2.Potassium sulphate
Potassium sulphate is one kind of potash fertilizer. Potassium sulphate consumption is far less than potassium chloride, which is less than 10% in international potash fertilizer market. It is suitable for a variety of crops, especially for tobacco, sugarcane, potato, sweet potato, grapes, tea and cruciferous crops (such as rape, beans, etc.). It is generally used for dry land rather than paddy field.

Organic fertilizer

Organic fertilizer is commonly known as farmyard manure or natural fertilizer, mainly from animals and plants. When it is applied to soil, it can supply carbonic materials for plants growth. It includes a variety of organic acid and rich nutrient elements. It not only provides complete balance of nutrients, but also has high manurial effect. Organic fertilizer can increase the content of organic matter, promote microorganism reproduction and change soil physical and chemical properties. Therefore, it is the main nutrient for green food.

1.Agricultural waste
Some agricultural wastes are good materials for organic fertilizer, such as straws, bean pulp, and cottonseed meal and so on. The wastes play an unique role in increasing soil nutrient and improving soil structure.
The main manure ways are used directly to field. The technology is simple to operate, while saving time and labor. Related experiments have shown that the soil porosity increases 2.1% to 4.1% after straw using to field for 2 to 3 years, organic material increasing 0.5 ~ 1.7g / kg, rapidly available potassium increasing 15.0 ~ 18.7mg / kg.

2.Livestock manure
These materials include pig manure, chicken manure and rabbit manure, etc. Livestock manure is one of natural fertilizer in agriculture.see more at: Chicken Manure Fertilizer Granulation Technology
Untreated livestock manure contains hazardous substance, such as escherichia coli, nematode and eggs. The application of untreated excrement rises temperature after fermentation, causing seedling burnt. To improve efficiency and reduce harm to crops and the environment, animal dung should be applied to field after complete composting.

3.Industrial waste
Some industrial waste are good materials for organic fertilizer, such as distilers’ grains, vinegar residue and sugar-free grains. On the one hand, the use of wastes in agriculture increases resource utilization rate and reduces environment pollution. On the other hand, it reduces the burden on industry and changes waste material into things of value.
4.Municipal sludge
Because of growing sewage treatment works, the production of municipal sludge is increasing year by year. Many people pay more attention to how to use it reasonably. Applying municipal sludge into agriculture is a good choice for urban construction.
River muck and sewage can be made into organic fertilizer. Because of complete component of the sludge, it just meets the requirements of nutrients in plants growth. Therefore, processed sludge can be used as fertilizer. It contributes to soil amelioration as well as reducing pollution. Not only solving the problem of waste treatment, but also is good for plants growth.

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The following points highlight the six important types of fertilizers. The types are: 1. Nitrogenous Fertilizers 2. Organic Nitrogenous Fertilizers 3. Phosphate Fertilizers 4. Potassic Fertilizers 5. Compound Fertilizers 6. Complete Fertilizers (NPK).

Type # 1. Nitrogenous Fertilizers:

The nitrogenous fertilizers are divided into four groups — nitrate, ammonia and ammonium salts, chemical compounds containing nitrogen in the amide form, and plant and animal byproducts.

(i) Sodium Nitrate:

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It occurs in natural deposits in northern Chile and is refined before use. The refined product contains about 16% nitrogen in the nitrate form, which renders it directly available to plants. For this reason it is applied as a source of nitrogen, specially to young plants and garden vegetables, which need readily available nitrogen for quick growth.

Sodium nitrate is easily soluble in water and is quickly leached out from the soil. It is particularly useful for acidic soils. Its continued and abundant use in soils causes de-flocculation and develop a bad physical condition in the regions of low rainfall.

(ii) Ammonium Sulphate:

It is the most widely used fertilizer in the country. It is a white crystalline salt, containing 20 to 21 % ammoniacal nitrogen. It is very suitable for wet­land crops, for example, paddy and jute. Ammonium sulphate is easy to handle and is stored well under dry conditions.

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It is also suitable for wheat, cotton, sugarcane, potatoes and many other crops grown on a wide variety of soils. Its continuous use increases soil acidity and lowers the yield. Its application to acid soils improves the yield of tea plantation considerably. It is advisable to use this fertilizer along with bulky organic manures to avoid its ill effects.

Ammonium sulphate can be applied before sowing, at sowing time, or as a top dressing to the growing crop. It should not be applied during germination, as in concentrated form it affects the germination very adversely.

(iii) Ammonium Nitrate:

Ammonium nitrate is a white crystalline salt, containing 33 to 35% nitrogen, 50% as nitrate nitrogen and another 50 percent as the ammonium form. In the ammonium form it is not leached out easily from the soil. It is quick-acting and highly hygroscopic and cannot be stored. Under certain conditions, it is explosive and, therefore, should be handled cautiously.

‘Nitro Chalk’ is the trade name of the product formed by mixing ammonium nitrate with about 40% of limestone or dolomite. It contains 20.5% nitrogen, 50% in the form of ammonia and half as nitrate. Its continuous use makes the soil acidic. The presence of lime makes it useful for acid soils.

(iv) Ammonium Sulphate Nitrate:

It is a mixture of ammonium sulphate and ammonium nitrate. It is available in a white crystalline form or as dirty white granules. It contains 26% nitrogen, three-fourths of it in the ammoniacal form and the rest as nitrate nitrogen.

It highly soluble in water and very quick-acting and non-explosive. It is useful for all crops. It slightly acidifies the soil. It is applied before sowing, during sowing or as a top dressing, but it is unsuitable for application along with the seeds.

(v) Ammonium Chloride:

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It is quite crystalline compound possessing a good physical condition. It contains 26% ammoniacal nitrogen. It is extensively used on paddy in Japan. It is used largely in- industries in India. It is similar to ammonium sulphate in action. It is not recommended for certain types of crops like tomatoes, tobacco, etc., as they may be injured by chlorine.

(vi) Urea:

Urea is a white crystalline organic compound. It is highly concentrated nitrogenous fertilizer containing 45 to 46% of organic nitrogen. It is highly hygroscopic and cannot be stored well in humid regions. To overcome this difficulty it is also produced in granular pellet forms coated with a non-hygroscopic inert material.

It is highly soluble in water and rapidly leached out from the soil. It is very quick-acting and rapidly changed into ammonia when applied. It is applied during sowing or as top-dressing but never during germination. It is suitable for most crops and can be applied to all types of soils.

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(vii) Calcium Ammonium Nitrate:

It is a fine, light brown or gray granular fertilizer. It is prepared from ammonium nitrate and ground limestone. It is almost neutral and can be applied even to acid soils. Its nitrogen content varies from 25 to 28 percent. Of the total nitrogen 50 percent remains in the ammoniacal form and the remaining 50 percent in nitrate form.

Type # 2. Organic Nitrogenous Fertilizers:

These fertilizers include plant and animal by-products, such as oil cakes, fish manure and dried blood from slaughter-houses. Before use by the crops these materials are converted by bacterial fermentation into utilizable ammonium-nitrogen and nitrate-nitrogen. These fertilizers are, therefore, slow acting, but supply available nitrogen for a longer period to the crops.

Oil-cakes are usually supplied as organic fertilizer throughout the country. They contain not only nitrogen but also some phosphoric acid and potash. A large quantity of organic matter is also present in the oil-cake. In addition to the three fertilizing constituents like, N, P2O5 and K2O, the oil-cakes contain 2 to 15 percent of oil.

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Dried blood or blood meal contains 10 to 12 percent highly available nitrogen and 1 to 2 percent phosphoric acid. It is effective on all types of crops and all types of soils.

Fish manure is available either as dried fish or as fish meal or powder. After extraction of oil from the fish the residue can be used as a manure, Fish manure contains 5 to 8 percent organic nitrogen and 4 to 6 percent of phosphoric acid. It is quick acting and suitable for all crops and soils. It is usually used as powder.

Type # 3. Phosphate Fertilizers:

Phosphate fertilizers are classified as natural phosphates, treated phosphates, by-product phosphates and chemical phosphates.

(i) Rock Phosphate:

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It occurs as natural deposits of rock in different countries. Very little rock phosphate is used directly as a fertilizer. Much more of it is used to manufacture superphosphate, the phosphoric acid of which is water soluble and becomes available to the crops.

(ii) Super phosphate:

It is the most widely used phosphoric fertilizer in India. It is now manufactured from ground phosphate rocks treating with sulphuric acid. The brownish- gray product after treatment contains mono-calcium phosphate and calcium sulphate (Gypsum) in practically equal quantities.

There are three grades of super phosphate:

Single superphosphate containing 16 to 20 percent phosphoric acid; di-calcium phosphate, 35 to 38 percent; and triple superphosphate, 44 to 49 percent.

Single superphosphate is the most commonly available grade in Indian market. The fertilizer is suitable for all crops and can be applied to all soils. It should be used along with organic manures in acid soils. It should be applied before or at sowing or transplanting.

(iii) Basic Slag:

Basic slag is a by-product of steel factories. It contains 6 to 20 percent of phosphoric acid (P2O5). The European slag contains 15 to 18 percent P2O5 and used as a popular phosphatic fertilizer in central Europe. But slag from Indian steel mills is poor in P2O5 and is not used as a fertilizer. The European slag is suitable for acid soils as it is alkaline in reaction. For effective use, it must be pulverized before application.

(iv) Bone-Meal:

The ground bone is called bone-meal. It is now widely used as phosphate fertilizer.

It is available in two forms:

(a) raw bone-meal

(b) steamed bone-meal.

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The steaming up bones under pressure removes fats, nitrogen and glue making substances. It contains 25 to 30 percent phosphoric acid. Steamed bones are more brittle and can be readily ground.

As it is slow acting, bone-meal should not be used as a top dressing. It must be incorporated into the soil in order to become available. It is applied either at sowing time or a few days before sowing and should be broadcast. It is particularly suitable for acid soils.

It is used for all crops. In some places of the country charred and powdered bones are used as manure. Charring destroys about 50 percent of nitrogen, but the whole of P2O5 remains in a quickly available form.

Type # 4. Potassic Fertilizers:

In India most of the soils contain sufficient amount of potash. So, potassic fertilizers are applied only to those soils which are deficient in potash.

Potassic fertilizers are used as:

(a) muriate of potash (potassium chloride)

(b) sulphate of potash (potassium sulphate).

(i) Muriate of Potash:

It is a gray crystalline material containing 50 to 63 percent of potash (K2O), the whole of which is available to the crops. It remains absorbed on the colloidal surfaces and is not leached out from the soil. It is applied at sowing time or before sowing.

(ii) Sulphate of Potash:

It is more costly as it is prepared by treating potassium chloride with magnesium sulphate. It contains 48 to 52 percent K2O. It dissolves readily in water and becomes available to the crops almost immediately after application. It can be applied at any time up to sowing. In certain crops like tobacco, chillies, potato and fruit-tree it is considered better than muriate of potash.

Type # 5. Compound Fertilizers:

These fertilizers contain two or three plant nutrients simultaneously. When both nitrogen and phosphorus are deficient in soil, a compound fertilizer, e.g., amorphous, can be used. It contains 16 percent nitrogen and 20 percent P2O5. Two different fertilizers can be mixed in correct proportion to produce the compound fertilizer.

Type # 6. Complete Fertilizer (NPK):

Compound fertilizers are not always well adapted to different kinds of soils. For that reason mixed fertilizers containing two or more materials in suitable proportions are used according to the needs of different soils. Mixtures usually fulfil the nutrient deficiencies in a more balanced manner and require less labour to apply than different fertilizers used separately.

These mixtures containing all the three principal nutrients (N, P and K) are called complete fertilizers as most soils usually remain deficient in these three elements. A special mixture for different crops are also produced by the manufacturers.

In some cases insecticides, fungicides and weed-killers, such as DDT, BHC and mercury or copper salts and 2, 4-D are mixed into the complete fertilizers. The component fertilizers must be compatible to ensure mutual reaction. Uneven mixing must be avoided. Bone- meal, muriate of potash and sulphate of potash can be mixed with all fertilizers.

Fertilizer For Boxwood Shrubs: Tips On Fertilizing Boxwoods

Healthy boxwood plants have lush green leaves, but to keep your shrubs looking their best, you may need to offer them boxwood plant food. When you see yellowing – foliage that turns a pale yellow or has marked yellow edges – it’s time to start reading up on boxwood fertilizer requirements. For more information on appropriate fertilizer for boxwood shrubs, read on.

Fertilizing Boxwoods

Your boxwoods may grow happily without added nutrition, depending on the soil. It’s best to get a soil test to figure out the product to use for boxwood fertilizing but, generally, loamy and clay soils require less fertilizer than sandy soils.

One sign that your shrubs lack nitrogen is a general yellowing of the lower, older boxwood leaves. Leaves get smaller and thinner and may

turn bronze in the winter if they receive inadequate nitrogen. They may also fall off earlier than normal.

Fertilizer for boxwood shrubs usually contains nitrogen, phosphorus and potassium as primary ingredients. The fertilizer formula is listed on the packaging with three numbers, reflecting these NPK percentages in the product.

Boxwood Fertilizer Requirements

Experts recommend that you use fertilizer with a 10-6-4 formula, unless your soil testing shows a specific deficit. When you are fertilizing boxwoods, you’ll want to be sure that the product includes magnesium, since this enhances the color of the shrub foliage. Using seaweed calcium as a boxwood plant food can also provide trace elements.

Tips on Boxwood Fertilizing

Apply boxwood plant food in the late fall for best results. Buy a granular fertilizer for boxwood shrubs and sprinkle the correct amount – listed on the packaging – around the base of the shrubs near the drip line.

This is the most effective way of meeting your boxwood fertilizer requirement since the most active roots are located near the drip line. You also avoid burning the roots by using surface application for boxwood fertilizing.

Don’t use too much fertilizer since this can be just as bad as inadequate amounts. It can kill the shrub. So apply the appropriate amount. To be even safer, broadcast the boxwood plant food over several inches of mulch after the area has been thoroughly irrigated.

Fertilizing Boxwood

By Teresa Odle

Boxwoods typically do not need regular fertilizing, but a few times a year, your shrubs might need a boost. Here are some tips on the best food for your boxwood, along with when and how to apply fertilizer.

When & Why to Fertilize Boxwood

Boxwoods benefit most from some fertilizing in spring to promote green growth or in late fall to promote root growth over winter. And know when not to add fertilizer: It’s never a good idea to fertilize boxwoods in the heat of summer, late in summer, or in winter. Fertilizing in late summer, before cool fall temperatures, can harm the plant by forcing new leaf growth just before winter cold and dormancy.

Best Fertilizer For Boxwood

Slow-release, balanced fertilizers are best for boxwood, and a granular form of urea fertilizer 10-6-4 is recommended. You also can use aged manure or cottonseed meal if your plant appears healthy, as long as you are making sure your boxwood has plenty of nitrogen. Lack of nitrogen shows up as yellowing of the shrub’s lower leaves. If that occurs, be sure to use urea or a balanced fertilizer with a little more nitrogen (N).

If your soil is not ideal (you can find out its pH through a soil analysis; check with your local cooperative extension office), you might need to adjust your food choice or add another soil nutrient. For example, if your soil’s pH is below about 6, add some dolomitic lime. You shouldn’t need to add the lime every time you fertilize; it remains active in the soil for years. But retesting the pH can tell you if you need to add more. If your pH is too high, try some iron sulfate to lower the level.

How to Apply Fertilizer to Boxwood

Try these tips for safely applying fertilizer to your boxwood:

  • Apply the fertilizer around the entire diameter of root growth. That means a few feet out from the area below the top (bushy canopy) of the plant. The roots you can’t see reach out further than your shrub.

  • Follow package directions for amount and apply the fertilizer evenly.

  • Follow the concept of “less is best” to start and add a little more next time if all goes well.

  • If you use a drip system for watering, be sure to place your fertilizer near the drip line; that is where roots likely have grown to and enables the water to carry the food down to roots.

Overfertilizing Boxwoods

Overfertilizing can cause more damage than no fertilizer at all. Don’t let the granules come in contact with the actual roots or leaves. If you see your boxwood’s pretty green foliage turning brown, you might have overfertilized or caused fertilizer burn. You can prevent overfertilizing by broadcasting particles around the plant and applying when the soil or mulch are slightly damp (apply fertilizer on top of mulch, not below). There is no need to fertilize boxwood with deep root fertilization; the shrub’s roots are shallow.

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ABOUT BOXWOOD / Frequently Asked Questions


The American Boxwood Society also recently held a seminar on Boxwood blight, Calonectria pseudonaviculata (also known as Cylindrocladium buxicola). . ABS will be hosting another seminar on Boxwood Blight and Boxwood Moth in Febuary of 2020 in Virginia. Please see our Events page for updates.
Outside Resources: Boxwood Blight Update by Saunders Brothers. USDA Boxwood Blight Fact Sheet.

Are boxwood susceptible to other pests and diseases?

The various pests and diseases that may affect boxwood vary to some extent according to specific plant species and cultivars. Common pests include leafminer, mites, and psyllid. Each of these should be controlled if infestation is severe or intolerable. Although nematodes and several types of fungi may infect boxwood, they are not usually major threats. Boxwood decline, presumably due to the fungus Paecilomyces buxi, is limited to B. sempervirens ‘Suffruticosa’, and is not a serious problem as it was several decades ago. It should be emphasized that deer will typically not eat boxwood, as the plant reportedly contains a toxic alkaloid.
Read more from our Boxwood Bulletin archives on Leafminer or

What new pests should I keep an eye out for?

Box tree moths, a major pest in the UK since 2006, were spotted in Ontario, Canada in August of 2018. Identification and treatment is key in preventing the spread of these pests. The European Boxwood and Topiary Society has a wonderful fact sheet on their website.

How do I know whether I should fertilize my boxwood?

There is no regular schedule to guide fertilization of boxwood. The most reliable guide to applying fertilizer is by testing the soil. Soil samples analysis by the Cooperative Extension Service will provide appropriate fertilizer recommendations for a specific site. If the boxwood begins to show symptoms of nitrogen deficiency, then it may be time to fertilize. The earliest symptom of nitrogen deficiency is yellowing of lower leaves. It will have a rather uniform yellowing, that is more pronounced on the older leaves inside the plant. The leaves then become smaller and thinner and turn quite bronze in winter. Boxwood leaves will normally stay on the plant for three years. If they fall off earlier, this may be a symptom of nitrogen deficiency.

What kind of fertilizer is best and when should I use it?

Granular, urea fertilizer with a 10-6-4, or similar, analysis will be appropriate in most situations. Late fall applications of fertilizer promote root growth and provide best results.

What is the best method to apply fertilizers?

Broadcast fertilizer around the base of the plant – just beyond the drip line. Surface application is the easiest and fastest technique. It is effective around the drip line because the most active roots are located there. Fertilizer particles that come into direct contact with the roots of unmulched boxwood can cause root bum. If the fertilizer is over applied, this will cause the foliage to brown and may even result in branches dying. This can be avoided by broadcasting fertilizers only on mulched boxwood when the soil has adequate moisture. Deep root fertilization, drilling holes and filling them partially with fertilizer, is not recommended. While it does eliminate volatilization of urea and ammonium it is not worth the effort. The roots of boxwood grow close to the surface and they do not benefit from deep root fertilization.

What does soil pH have to do with fertilizer?

The pH needs to be in a proper range in order for the nutrients to be available to the plant. The optimum soil pH for boxwood is between 6.8 and 7.5. If the pH is below the recommended range, add dolomitic lime. This lime has low oxide content and will persist in the soil for 4–7 years depending on application rates and soil type. Your County Extension Service is an excellent resource for recommendations for properly adjusting soil pH. A soil test analysis always provides the most reliable guide to determine if the pH or nutrients need to be adjusted, and to the appropriate degree.

How are boxwood propagated?

By far the most widely used method is stem cuttings, which will produce plants identical to the parent plants. Cuttings, best taken from parent plants from July to December, should be removed from one year old branchlets and placed into containers filled with one of several appropriate media mixes. With frequent watering, rooting usually takes place in two to three months. Boxwood can also be grown by layering, in which roots develop on a stem of a parent plant. Finally, plants can be grown from seedlings, but they can be somewhat variable from the parent plant. Back to Top

LEARN MORE:

How can I learn more about boxwood?

Detailed sourcebooks for boxwood are few. The most highly recommended was Boxwood Handbook: A practical guide to knowing and growing boxwood. The author, Lynn R. Batdorf, is the curator of the National Boxwood Collection at the U. S. National Arboretum in Washington, D.C. and is the ABS Registrar for the International Cultivar Registration Authority for Buxus L.

Have further questions?

Email The American Boxwood Society at [email protected]

Boxwood – Pruning, Winter Care and Fertilizing

This shrub all often used in mass or as a hedge but their care can be the same if used as a specimen. Pruning should be done in early spring before leafing out. Shear or prune outer branch tips to shape and reduce size. Repeat pruning through summer as needed. For best results pruning should start when the plant is young and stayed with year to year. As the plant matures pruning or shearing can shift to early Summer after the new growth has matured. With rather dense hedges pick pruning should also be done to increase the longevity of the plant. This is done by cutting small holes in the surface of the hedge to let light into the interior of the plant and promote inside budding. This allows you to shear the plants for a longer time without letting the plants get too large.

This plant grows and develops best in acidic soil. Most of the soil, all of the rainwater and all of the ground water in southeastern Wisconsin is basic or alkaline. Therefore, for some plants to thrive, they need to have special care.

Initially, the soil the plant is installed into should be amended to make it more acidic and to increase the amount of organic matter in the soil. Over time, the soils acidity should be supplemented with an acid-based fertilizer. A liquid fertilizer, Miracid works well. This liquid fertilizer is mixed with water and applied the same as you would water the plant (see product for specific details). This type of fertilization should be done three or four times per year, starting in April and ending by the mid-July. Soil can also be acidified with soil sulfur, aluminum sulfate or cotton seed meal, however, these products will not fertilize the plant. Mulch is also important to acid loving plants. A 2-4″ thickness of bark or needle mulch should surround the plant at least as far out as its drip line.

These evergreens will perform well through most winters. In severe winters, however, they may discolor, but will bounce back in spring. Winter protection may be needed, however, for the first few years after installation, or if the plant has been under stress. To protect the plant, spray it with an anti-transpirant (such as Wilt-Pruf) in mid to late November. The timing for this application can be somewhat tricky. The temperature must be above 40 degrees, and it cannot rain on the plant after the product has been applied. The plant can also be protected by wrapping it in burlap, or enclosing it in a burlap tent. This form of protection will keep the wind and sun off, but will not cut off air flow or trap heat, which can be harmful to the plant. A burlap tent is made by setting three wooden stakes into the ground around the plant and stapling burlap to it on all three sides. The top of this tee-pee like structure should be left open. If the plant is in open soil it should be mulched and get a good watering in early November if the soil is dry. Watering in late fall is very important for the winter health of any evergreen and should be done to young plants every year in early November. Even more mature plants can benefit from late season waterings, especially after a dry fall season.

Mistakes to Avoid when Growing a Boxwood

Boxwood is one common type of shrub found in many public and private gardens everywhere. Boxwood shrubs are very versatile and can be used as hedges, parterres, individual, or even in containers or topiary. While most people think there are merely two types of boxwood—American and English—there are actually around 160 different cultivars. Of these 160 there are around 115 available commercially to you.

General Information

Boxwood is considered a simple low-maintenance shrub overall, but there are some general guidelines to follow when planting boxwood shrubs. The fall season is the ideal time to plant boxwood. Any pruning or thinning that needs to be does is best in the winter. Boxwoods can also be planted in the spring and summer with special attention paid to protecting your plants from insects and keeping them well watered. For best results use a soft or clay soil.

Insects and Disease

Insects and disease to worry about will typically vary depending on the type of cultivar you choose. The most common pests include mites, leafminer, as well as psyllid. Any of these pests need to be treated as soon as possible if infestation is severe. There are also types of fungi that may infect boxwood they are not normally a serious issue. Only a few types of boxwood have experienced any decline and the threat is not nearly as severe as it was in the past. Most animals will not feed on boxwoods because of the toxin alkaloid they reportedly contain.

Propagation

The most commonly used method to propagate boxwood shrubs is stem cutting. This method will give you new shrubs identical to those from which you took the cutting. The cuttings should, for best results, be taken from the 1-year old parent plant between July and December and put into a container with the appropriate mix of soil and fertilizer. The roots will develop in 2 to 3 months. You can plant seeds directly or layer the roots but both methods may yield slightly different variations of your boxwood.

When to Fertilize?

There is no set method as to when or how often you must fertilize your boxwood shrubs. The most specific way to determine the best results is to have the soil professionally tested. The simpler method is to look for indications of nitrogen deficiency in the boxwood. The first sign of nitrogen deficiency is the yellowing of the lower older leaves. Leaves will typically last on boxwoods for 3 years. If you notice them dropping earlier, that may also indicate a nitrogen deficiency and indicate a need for fertilization.

Fertilizer

The best type of fertilizer to use on boxwood shrubs is a granular with a 10-6-4 or close analysis. The best time to apply fertilizer is in the late fall to get the best results of growth. Surface application around the base line of the shrubs is the quickest and easiest method to apply fertilizer. For best results and to avoid over fertilization try to apply the fertilizer when the soil is moist and over mulch if possible.

When it burst upon the scene five years ago, boxwood blight put a big scare into Virginia nurseries and all who love the iconic shrub, though perhaps some who scorn it for its historical associations and acrid smell would just as soon see the genus in its grave. Much like a sci-fi movie, sticky spores attach to anything that’s been in contact with infected plants (pruners, shoes, gloves, old leaves) and pathogens live in the soil for five to six years. The afflicted drop their leaves, decline and die. Labeled a “devastating disease” by the Virginia Cooperative Extension, it wreaked havoc among old English and American varieties before nurseries learned to control it with strict hygiene and reliance on resistant varieties.

Robert Saunders, who grows boxwoods with his brothers just south of Lovingston, says things have settled down since the blight was discovered in 2011. He sees it now as manageable, but “the days of planting large numbers of English boxwood are over.” So, if you have some ancient specimens on grounds—soft fluffy English or burly dark American—now’s the time to protect them. Never prune boxwood in wet weather or subject them to overhead irrigation.

Unlike English and American (Buxus sempervirens), littleleaf boxwood (B. microphylla) produces cultivars apparently highly resistant to the fungus. Green Beauty, Wintergreen and Winter Gem are among the most highly ranked for resistance.

The gist is, if you have extensive old boxwood plantings, do not let people care for them who have tramped through lots of other peoples’ boxwoods until they tell you exactly what precautions they are taking (sterilizing tools, replacing coverings on shoes, etc.). It’s in everybody’s interest to do this.

In the meantime, keep your boxwoods well-groomed, with old twigs and debris cleaned out from the center of plants and do not overmulch. Air circulation and keeping infection out of the area are key. If you want to opt out of the whole drama altogether, consider inkberry and hollies for your deer-resistant evergreen needs.

Boxwood cares aside, spring is upon us, with winter jasmine and snowdrops having fully flowered at the end of January. Garden centers will be ready, with most opening March 1. Our last frost date still hovers around mid-May, so be careful setting out tender annuals unless you’re able to toss frost cloth or sheets over them on the frigid nights we’re bound to get at least through the end of March.

Cool season annuals like pansies, violas and sweet William are good choices for early color until the soil heats up. Buy tomatoes as soon as they go on sale to get a wide selection of varieties, but keep them potted so you can whisk them inside if needed before planting them when the earth has thoroughly warmed in May.

Now is the time to fertilize hollies, azaleas and dogwoods with an acidic product like Holly Tone. Pull back existing mulch, scatter fertilizer and lightly scratch in with a garden claw or rake before replacing the mulch. Boxwoods, however, need very little fertilizer and prefer a slightly alkaline soil, so keep Holly Tone away from them.

Resist the temptation to recarpet all beds with a nice thick layer of fresh shredded hardwood. If you’ve already got 2-3″, rake it up a bit to break the crust and wait until fall to add more. Too much mulch smothers plants and roots, sheds water and invites voles.

Always something to worry about in the garden. Love them or leave them, let us take a lesson in resilience from the boxwoods and welcome spring, ready to deal with whatever challenges nature has in store.

Spring checklist

  • Drop off lawnmower blades, hand pruners and other cutting implements at Martin Hardware for sharpening.
  • Check oil and gas for mowers.
  • Clean and oil hand tools. Sharpen shovel and spade blades with a bastard file.
  • Prune roses and fertilize with compost and well-rotted manure.
  • Fertilize perennials with compost or organic slow-release 5-10-5 product.
  • Top-dress bare spots in the lawn with compost before seeding and strawing.
  • Start indoor seeds—tomatoes, cleomes, zinnias—for setting out in mid-May.
  • Sow cool-weather greens —arugula, cilantro, kale, lettuce, mesclun—outdoors.

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