- Fertilizing Flower Gardens and Avoid Too Much Phosphorus
- Lilac Plant Fertilizer: Learn How And When To Feed A Lilac Bush
- When to Feed a Lilac
- How to Fertilize Lilac Shrubs
- General Lilac Care
- Three Tips for Growing Lilac Bushes
- Lilac tree – Pruning, Winter Care and Fertilizing
- 3 tips for growing lilac bushes
- Learn About Lilacs
Fertilizing Flower Gardens and Avoid Too Much Phosphorus
Most home garden fertilizers are complete fertilizers, which contain the macronutrients required by plants in the largest amounts. The numbers on a fertilizer bag refer to the percentage of nitrogen (N), phosphorus (P2O5) and potassium (K2O) (in this order).
Complete fertilizers sold as “all-purpose” fertilizers for gardens, such as 24-8-16 or 12-4-8 often contain higher amounts of nitrogen (the first number) than phosphorus or potassium. However, complete fertilizers sold for flowering plants (including roses and bulbs) such as 15-30-50 or 10-30-20 contain higher amounts of phosphorus (the second number) than nitrogen or potassium and are often labeled as “blossom or bloom booster”. The use of high phosphorus fertilizers originates from the need for phosphorus on agricultural fields heavily used for crop production which were deficient in phosphorus. However, most non-agricultural soils contain adequate amounts of phosphorus.
All three of the major nutrients are necessary for plant health. In general, Nitrogen is often required in the largest amount. Nitrogen is an integral part of chlorophyll manufacture through photosynthesis, stimulates green leafy growth and promotes fruit and seed development; Phosphorus supports the transfer of energy throughout the plant for root development and flowering; Potassium is essential for photosynthesis and regulates many metabolic processes required for growth, fruit and seed development.
Avoid Over-Applications of Phosphorus
Do home gardeners and landscapers really need to apply high phosphorus fertilizers to get gorgeous blooms?
Answer – it depends. Most non-agricultural soils (unless acid sandy) contain adequate amounts of phosphorus. A soil test is the only way to know for sure if a flower garden needs phosphorus.
What harm could it do to apply extra phosphorus?
Answer – Excess phosphorus (and potassium) can be detrimental to the environment by moving in runoff water and posing a threat to water quality. Aquatic plants are limited by phosphate and the addition of phosphate will induce algal blooms (eutrophication). Algal blooms are followed by increased bacterial activity, resulting in lowered oxygen levels and the eventual death of fish and other animals.
Also, high levels of phosphorus, either from chemical fertilizers or natural sources such as bone meal or rock phosphate, can inhibit growth of beneficial soil organisms called mycorrhizal fungi. Without beneficial organisms, plants must put additional resources into root growth at the expense of other tissues and functions.
Nitrogen is much more likely to be limiting in gardens. Nitrogen deficiency is characterized by overall leaf yellowing (chlorosis). Among other things, the lack of nitrogen reduces the plant’s ability to take up phosphorus. When nitrogen is restored to optimal levels, the plant’s ability to use phosphorus from the soil is markedly improved. It’s important to realize that when nitrogen is deficient it does not necessarily follow that other nutrients must be deficient as well.
So, don’t guess, soil test. The UMass Soil and Plant Nutrient Testing Laboratory offers soil testing for landscapes and gardens.
Once you receive your soil test report and recommendations from the UMass Extension Soil Test Laboratory:
- Calculate the square foot area of the flower garden.
- Calculate how much fertilizer to use.
- Apply limestone, if needed according to the soil test recommendation.
- Apply fertilizer based on the recommendation and calculation described below.
How to Calculate the Square Foot Area of the Flower Garden
For flower beds, lime and fertilizer recommendations by the UMass Extension Soil Test Laboratory are provided for a 100 square foot area. Therefore, you need to determine the size of your garden before spreading lime or fertilizer. The length multiplied by the width of the garden will give you the total area. For example, a garden 5 feet wide and 10 feet across would be an area of 50 square feet. Often flower gardens are irregularly shaped and the square footage would need to be estimated.
How to Determine How Much Fertilizer to Use Based on Soil Test Recommendations
The numbers on a fertilizer bag refer to the percentage of nitrogen (N), phosphorus (P2O5) and potassium (K2O) (in this order).
To determine how much fertilizer to use, divide the lbs. of the specific fertilizer material recommended in the soil test result by the percent of that same material in the fertilizer being used. First, convert the number to its decimal form when using percentages in calculations.
The soil test recommends 0.25 lb. of nitrogen per 100 sq. ft. and you plan to use a 10-5-10 fertilizer, then this is how to figure how much fertilizer to use to supply 0.25 lb. of nitrogen.
Use of Organic Matter
The addition of organic matter to very sandy soils or those low in organic matter can be very beneficial. Organic matter will increase both the water and nutrient holding capacity of the soil, moderate soil temperatures, encourage earthworm and other soil organism activity, increase soil nutrient levels, enhance the soil’s structure and make it easier for plant roots to penetrate the soil. Sources of organic matter include peat moss, leaf mold, rotted manure, bagged humus or compost. The use of organic mulch such as straw or bark mulch will also add soil organic matter as it decomposes.
Care should be taken when using composts, manures or other materials that are potentially high in nutrients as a source of organic matter. Heavy continuous use of compost can lead to imbalances or excess levels of some nutrients after a number of years. As with any soil amendment, it is advisable to periodically test your soil for nutrient levels, pH and organic matter and adjust your fertilizer and organic matter applications accordingly.
Guidelines for How and When to Fertilize Flowering Plants
Use the amount of fertilizer recommended on the soil test report at the times of year listed below for the type of flowering plants being grown. Note that these are guidelines. Plant health, types of fertilizers, weather conditions, soil types and other factors influence plant nutrient needs and timing of application.
For new flower beds, work the fertilizer into the top 4 to 6 inches of soil before planting. For established plantings, spread the fertilizer evenly around the plants and lightly rake it into the soil, then water thoroughly. If possible, pull back the mulch around plants so the fertilizer is applied to the soil and not on top of the mulch.
Annuals – Apply fertilizer during flower bed preparation. Make a second application at the same rate 6 to 8 weeks later. Annual selections that will continue blooming into fall may benefit from a third application at the same rate made in late August.
Perennials and Ornamental Grasses (new plantings) – Apply fertilizer during flower bed preparation. Make a second application at the same rate 6 to 8 weeks later.
Perennials and Ornamental Grasses (established plantings) – Apply fertilizer when growth resumes in the spring. Perennials with long lasting foliage or extended bloom periods may benefit from a second application at the same rate 6 to 8 weeks later.
Spring Flowering Bulbs – Do not apply bone meal or other source of phosphorus unless a soil test indicates it is needed. Apply fertilizer as soon as new growth emerges in the spring. Also apply fertilizer at the same rate when preparing beds in late August or early September.
Summer Flowering Bulbs – Apply fertilizer at planting time or, in the case of hardy summer flowering bulbs, when growth resumes in the spring. Make a second application at the same rate after flowering for plants with short flowering periods. For plants with long flowering periods such as cannas and dahlias, make a second fertilizer application at the same rate in mid-July.
Roses – Make separate applications of fertilizer in May, June and July. Do not fertilize after mid-July as new growth may be encouraged. It most likely will not have time to harden off properly in the fall and will be very susceptible to winter kill.
Wildflowers – Wildflowers that are native to New England’s woodlands or meadows generally have low nutrient requirements. Apply fertilizer once in the spring as new growth begins, or during bed preparation.
Types of Fertilizers for Flowers
There are several ways to supply nutrients to flowering plants. These include granular chemical fertilizers, which may or may not be controlled-release, water soluble fertilizer and organic fertilizers. Controlled-release fertilizers are also called continuous feed, slow-release or timed-release.
Granular fertilizer formulations that are not controlled – release will generally supply nutrients to the plants for about 6 to 8 weeks. During periods of excessive rainfall or frequent irrigation, the nutrients may be leached out of the soil and fertilizer may need to be reapplied.
Controlled (Continuous) – release granular fertilizers consist of water soluble fertilizer that is encased in a semi-permeable resin coating. When they come in contact with water, small amounts of nutrients are released to the soil for use by the plant. The rate of nutrient release for most of these fertilizers is regulated by temperature. The warmer the temperature the faster nutrients are released. When the initial fertilizer has been depleted, fertilizer will need to be re-applied. Many of the products for use with flowers will supply nutrients for 3-4 months depending on the temperature and amount of moisture.
Some gardeners may also prefer to use water-soluble fertilizer formulations. Water-soluble fertilizers are purchased ready to use or as a concentrated powder or liquid fertilizer that is mixed with water and applied to either the soil, or to both the soil and the plant’s foliage. Since the nutrients are in a soluble form, they are subject to leaching (movement through the soil). Because these nutrients are available for only a short period of time, the label of a water-soluble fertilizer will direct you to apply it at more frequent intervals than when using a granular or controlled- release formulation. In the flower garden liquid fertilizer is useful for a quick boost or to supplement granular or controlled-release fertilizers when then they have been depleted. However, most gardeners prefer products that do not have to be constantly reapplied.
Organic fertilizers can also be used to supply nutrients to flowering plants. They can be purchased as complete fertilizers or for individual nutrients and as liquids or solid bulk forms. Organic fertilizers are often lower in nutrient analysis and solubility than synthetic fertilizers. So, they may need to be applied at higher rates and greater attention should be given to soil preparation during the initial stages of bed preparation to ensure uniform distribution. Thoroughly incorporate organic fertilizers into the soil.
Lilac Plant Fertilizer: Learn How And When To Feed A Lilac Bush
There are over 800 cultivars of lilacs with plants that bloom in hues of blue, purple, white, pink and magenta. Lilacs grow well in sunny locations with slightly alkaline to neutral soil and require little more than occasional pruning and lilac plant fertilizer. Learn how to fertilize lilac shrubs to promote the best and most prolific scented blooms.
The scent is unmistakable and intoxicating. Lilacs have been in cultivation for at least 500 years and represent old money and crumbling mansions. The bushes are hardy and require little attention, including fertilizer, except in nutrient poor regions. For those plants, rejuvenation pruning might be a better answer but you can also apply lilac plant fertilizer in spring for added health. Knowing when to feed a lilac will promote better blooms and avoid heavy foliage.
When to Feed a Lilac
Plant food helps promote better leafy growth, healthy roots and better nutrient and water uptake, as well as better blooming and production.
The ratio in fertilizer refers to NPK, which are the macronutrients a plant needs for optimum health. They are nitrogen, phosphorus and potassium. Plants with a high first number are formulated to enhance leafy growth, while phosphorus and potassium spur root health and flower and fruit production.
Fertilizing lilacs with anything but a balanced fertilizer can create excessive foliage or heavy blooms. The best lilac plant fertilizer is a closely balanced fertilizer applied when active growth is just beginning. Since lilacs are deciduous, this is in spring just as the canes begin to awaken.
How to Fertilize Lilac Shrubs
Bone meal is a great fertilizer for lilac bushes. This is because it makes soil more alkaline. It is a natural plant food easy for the lilac to intake.
Fertilizing lilacs isn’t strictly necessary except after the first and second years of planting. They may be fertilized at planting with a superphosphate and limestone to sweeten the soil and avoid excess acidity.
As long as the soil is the proper balance and there is plenty of organic matter, you can forgo traditional fertilizer mixes. Only bushes planted in poor soil will really benefit from annual feeding. Use a 5-10-10 ratio when you do feed the plants. Spread 1 cup granular food evenly around the root zone of the plant and water into the soil.
General Lilac Care
For old, poorly cared for plants that have become tangled masses of suckers, prune the bushes after bloom to rejuvenate them.
A fertilizer for lilac bushes can be applied in early spring but a better way to reinvigorate these tired old plants is by pruning out 1/3 of the old canes for 3 successive seasons. This will allow fresh growth to emerge while still permitting the blooms to grow. Prune off the spent blooms to make room for the next season’s flower buds to grow.
Three Tips for Growing Lilac Bushes
I am not sure if there exists a better smell than lilacs on a breezy summer night. What’s more, their bright green foliage and clusters of tiny purple flowers bring a soft beauty to your yard. While lilac bushes are a fairly low-maintenance perennial plant, they do grow better with a bit of human assistance. Here are three tips for growing lilacs, from horticulturists at university extension services.
Prune those lilac bushes: The Ohio State University Extension Service says that pruning is one of the most important ways that you can help a mature lilac bush to flower abundantly. Lilac bushes do not need to be pruned in their first three years of growth. The young shoots that grow during the first few years are important for long-term growth, so let them be. After that time period passes, trim away large woody branches in the late spring, after the last blooms of the season have fallen, but remove less than one-third of the branches per year. You should focus your efforts on cutting away the old weaker wood from the center of the bush. Do not prune from the top of the bush; instead, trim the older branches that you can reach from the bottom.
Plant those lilac bushes in the sun: According to the Utah State University Extension Service, lilac bushes need at least eight hours of sunlight every day to achieve their full potential for gorgeous, fragrant blooms. Also, lilac plants like well-drained soil. Nevertheless, lilac bushes are hardy and can survive in partial shade and wetter soil. They won’t produce as many blooms, but you will see some blossoms even in non-ideal conditions. The fact that lilacs are so low maintenance is one of the many advantages of growing them.
Get your soil chemistry right: The Cornell Cooperative Extension of Chemung County claims that lilacs like slightly acidic to alkaline soil, with a fairly low level of nitrogen. It is best to transplant new bushes in the fall, after the leaves have fallen but before the ground freezes. Prior to planting, have your soil tested to find out whether it needs to be amended at all. Avoid nitrogen-rich fertilizers. Although lilacs do like potash and phosphate, the bushes don’t need much fertilizing. Bone meal is recommended for lilacs because it makes soil more alkaline.
Because lilac bushes are so hardy, they don’t need too much maintenance other than pruning, and can thrive in many locales, in Hardiness Zones 3 through 7. However, do watch out for slugs and snails, as well as powdery mildew, which is the disease that most frequently attacks lilacs. If you notice a dusty, white coating on your lilac foliage, act quickly with a dusting of sulfur. Your effort will reward you with fragrant and robust lilac plants for years to come.
Are you looking for an expert to plant lilacs and other lovely flowering shrubs for you? Find a reliable professional landscaper.
Updated March 7, 2018.
Lilac tree – Pruning, Winter Care and Fertilizing
Lilac Japanese tree, including reticulata and pekingensis.
These trees should be pruned in early spring, before the sap starts to flow (March). This will remove some spring flowers. Pruning can also be done in summer, after the leaves are full size. This plant should not be sheared.
The time to make a long lasting effect on the form and structure of the plant is when the tree is young. Crossing or crowded branches, suckers and water sprouts should be removed. Low branches should also be removed, if desired, when the tree is young. This is best done by removing one or two branches a year, over a period of a few years, until the needed clearance is obtained. As the tree gets older, pruning every three to five years will keep the tree in good general shape. Water sprouts and suckers, however, should be removed each year.
By fertilizing young trees you can increase both the size and the amount of flowers on the plant. Granular, liquid or stake type fertilizers can be used. Granular types should be worked into the soil around the plant at a rate of 2 pounds or 2 pints per 100 square feet of planting bed. An alternative way is to drill or punch 6″ deep holes at the drip line of the plant. Poured into these holes should be a total of 1/4 pound of fertilizer per foot of height or spread of the shrub (divided up and poured evenly between all of the holes). These holes should not be filled with more than 1/3 of the fertilizer and then they should be top filled with soil. This method of fertilization should only be done once a year, and is best done in late fall after leaf drop, or in early spring before bud break.
Liquid fertilizers (such as Miracle Gro) are mixed with water and applied the same as you would water the plant (see product for specific details). This should be done three or four times per year starting in late April and ending in mid July. Stake type fertilizers can be used following the directions on the package. With any of the above techniques a balanced mix should be used, 20-20-20 or 20-30-20 or 18-24-16. Organic fertilizers, like manure, can also be used with good results. The material should be worked into open soil at a rate of one bushel per one 6′ shrub or 100 sq. ft. of bed area.
These trees need little winter care but, should be checked now and then for rabbit or other damage. If rabbit damage is found you can protect the plant with a fence formed with hardware cloth (looks like chicken wire but, with small square holes). The plant is tied in if necessary, then a section of hardware cloth is put around the outside. The base of the cloth is buried in the soil or mulch. This protection should be installed in late November and removed in mid April.
3 tips for growing lilac bushes
Is there a better smell than the fragrance of lilacs on a breezy summer night? Also, their bright green foliage and clusters of tiny purple flowers bring a soft beauty to a backyard or front yard. While lilac bushes are a fairly low-maintenance perennial plant, they do grow better with a bit of human assistance. Here are three tips for growing lilacs, from horticulturists at university extension services.
Prune those lilac bushes: According to the Ohio State University Extension Service, pruning is one of the most important ways that you can help your lilac bush to flower. Lilac bushes do not need to be pruned in their first three years of growth. The young shoots that grow during the first few years are important for long-term growth, so let them be. After that time period passes, trim away large woody branches, but remove less than one-third of the branches every year. The wood that you should focus on removing once a year, after the last blooms have fallen, is the old weaker wood from the center of the bush. Do not prune from the top of the bush; focus on the older branches that you can reach from the bottom of the bush.
Learn About Lilacs
Common Disease Problems
Bacterial Blight: This usually only occurs on young plants in warm weather. Small oozing cankers appear on the branches and buds. Cankers may continue to completely encircle infected branches, eventually killing them. Burpee Recommends: Practice good garden hygiene at the end of the season and discard, do not compost, possibly diseased plants and plant parts. Space plants to allow for adequate air circulation. Prune all infected branches below cankers. Contact your Cooperative Extension Service for recommendations.
Bacterial Leaf Spot: First signs are small translucent spots with a broad yellowish edge that slowly enlarge and become angular or irregularly circular with a reddish center. It thrives in cooler temperatures. The disease may also affect and disfigure flower heads. Burpee Recommends: Remove infected plants. Avoid overhead watering. Do not work around plants when they are wet.
Powdery Mildew: This fungus disease occurs on the top of the leaves in humid weather conditions. The leaves appear to have a whitish or greyish surface and may curl. Burpee Recommends: Avoid powdery mildew by providing good air circulation for the plants by good spacing and pruning. Contact your Cooperative Extension Service for fungicide recommendations. Some lilac varieties are resistant.
Common Pest and Cultural Problems
Lilac Leafminers: These insects bore just under the leaf surface causing irregular serpentine lines. The larvae are yellow cylindrical maggots and the adults are small black and yellow flies. They do not usually kill plants, but disfigure the foliage. Burpee Recommends: Remove affected foliage. Sanitation is important so be sure to remove all debris at the end of the season.
Scale: Small bugs look like brown, black, gray to white bumps on the stems of plants. Scale may not have any apparent legs and may not move. Scales have a sucking mouth part. Scale may produce honeydew so leaves and stems may be sticky. Scale can weaken the plant causing it to grow very slowly and it may wilt at the middle of the day. Burpee Recommends: Completely spray the stems with insecticidal soap. For a severe infestation contact your local County Extension Service for recommendations for your area.
Spider Mites: These tiny spider-like pests are about the size of a grain of pepper. They may be red, black, brown or yellow. They suck on the plant juices removing chlorophyll and injecting toxins which cause white dots on the foliage. There is often webbing visible on the plant. They cause the foliage to turn yellow and become dry and stippled. They multiply quickly and thrive in dry conditions. Burpee Recommends: Spider mites may be controlled with a forceful spray every other day. Try hot pepper wax or insecticidal soap. Check with your Cooperative Extension Service for miticide recommendations.