When to transplant hostas?

Transplanting Hostas

What’s better than one hosta? More hostas! It’s not hard to tackle transplanting hostas, either from divisions or fresh-from-the-nursery pots. Dividing hostas is another easy process, although with large, established clumps it can require a little elbow grease. Learn what you need to know for splitting hostas successfully.
Transplanting hostas is a quick and easy chore. Maybe you’re moving plants because they’re not in ideal growing conditions and looking a little less than picture-perfect. Hostas that have brown leaf margins or odd color spots on leaves are candidates for moving. To dig a hosta for transplanting, if you’re working in early spring, simply dig as much of the rootball as possible.
If you’re transplanting hostas when they’re fully leafed out, tie leaves up with string or cut them a few inches above ground level (they’ll regrow later). Then dig as much of the rootball as possible. Tuck hostas into planting beds with soil that’s rich and well-drained. Add some kind of organic matter to planting holes and beds. Set a hosta plant into soil so the rootball is at the same depth in soil as it was in the pot. Firm soil around the plant, and water well. Add mulch to help suppress weeds and maintain soil moisture.
When dividing hostas, first ask yourself why. Hostas are a perennial that grows best when it’s left alone. The longer a clump stays in the ground, the bigger it becomes. Hostas don’t typically need dividing unless they have outgrown a space. In most cases, even when a hosta has filled it growing area, the resulting root restriction doesn’t damage the plant but simply reduces the growth rate.
If you’re considering splitting hostas because your plant isn’t doing well, the growing conditions probably aren’t ideal. Other perennials, like yarrow, garden mums or coneflower, send out a clue they need divided when the center clump of the plant dies. Hostas don’t work that way. Many of the giant types actually need about five years to come into their own. Dividing hostas like these sooner simply reduces their growth potential.
Splitting hostas is best done in spring or early fall. Ideally, plan on dividing hostas before spring or fall rains arrive. Hostas suffer most when they lose roots, so dig as much of the rootball as possible. If you just need a few divisions, dig small clumps that have formed beside the larger parent clump. If your goal is dividing large hosta plants into several viable clumps, insert a spade into soil outside the dripline of leaves. Use a sharp spade, cutting into soil in a circle surrounding the entire plant.
Pry the plant out of the ground. With mature hostas, you may have to dig 18 inches down to get the roots. Unearth clumps onto a tarp. Pull apart clumps with your hands, or use a knife to slice crowns or growing points away from the mother plant. An easy method for dividing hostas is cutting a clump into thirds or fourths and replanting those pieces . Using this method, in one growing season plants fill in so much that it’s tough to tell they were divisions.

Irene asks, “When can hostas be divided and transplanted?”

The best time to divide and transplant hostas is in August or September, about a month before your first frost date. Hostas respond well to early fall division because:

  • Fall growth spurt: When the midsummer heat eases off and rains return, hostas often have a growth spurt. Dividing during this growth spurt will help them establish new roots quickly. If you’re planning to make tiny divisions (to turn one hosta into ten), fall is definitely the best season.
  • Spring success: By next spring, the plant will be well established and will sprout more mature looking leaves, giving a better appearance.

Many gardeners prefer to divide hostas in spring, because it’s easier to see the clumps before the leaves get so huge. This may be more convenient, but keep in mind that spring divided hostas have some risks:

  • Growth:Spring divisions often look scraggly the first year, because the stress of transplanting will stunt the leaves. If you must divide in spring, make very large divisions that leave a substantial clump intact.
  • Health: Hosta divisions are also more susceptible to severe spring weather. Hostas put out leaves first, and roots second. If you interrupt the spring leaf burst, you’ll delay root formation for a month or more, leaving your new hostas vulnerable to the cool soil, drying winds, and unpredictable heat waves of spring.

Hosta Dividing Tips

Whenever you divide your hostas, keep these tips in mind:

  • Plant Age: Hostas that are around three years old generally transplant best – they’re large enough to divide while not being too dense to cut apart.
  • Heat and Drought: Severe heat and drought are dangerous to newly divided hostas. Keep them well watered, especially if the humidity is low.

Further Information

  • Bob Solberg’s Hosta Gardening Tips

Dividing Hostas

What is better then a hosta?…two hostas of course! Dividing your hostas could not be easier. We are always asked by worried hosta enthusiasts how and when to divide hostas as to not damage them. Dividing your hostas keeps them healthy and vigorous when done in the right way at the right time.

Whether your hostas are in pots or in the ground the method for splitting is the same. Remove from the pot or dig out of the ground and shake off as much soil from the roots as you can. Once you have removed some soil you will be able to see more clearly what you are cutting or pulling, reducing the chances of damaging the plant. You can divide with a spade, knife or your hands depending on the size and density of the clump. I personally prefer to divide with my hands where possible.

Find a central point in the clump avoiding as many buds or stems as possible and cut through. If you are dividing with you hands you can just ease the plant apart. Do not worry if you damage any buds or stems as this will not harm the plant. Remove any damaged foliage and put the divisions in a bucket of water to soak for 5-10 mins before planting or potting up. Be sure to always disinfect any tools, surfaces and your hands in between plants to avoid transferring any virus’ or fungal disease between plants.

(Root bound hosta divided with a knife)

When should hostas be divided?

Many people don’t know exactly when the best time to divide their hostas is. The answer is there are two periods of the year when division is best carried out, Spring and Autumn. Dividing hostas in the Spring should be done as the early buds start to appear, this will allow you to see where you should make the division. When divided in the Spring your hostas will have plenty of time to root and put on new growth that same year.

Dividing in the early Autumn is often the preferred choice by many people as it usually means very little watering is required once you have planted your new divisions out.

On the nursery we divide all year round but aim to do as much as we can in the Autumn. Dividing in the Summer is fine as long as the divisions are kept well watered. Plants divided in the Winter do not put on any new growth straight away and the ground is usually frozen so it is usually best to wait until Spring if possible.

How often can I divide my hosta?

Hostas can be divided reasonably regularly depending on the variety, slower growing varieties will need longer to recover where as vigorous varieties can be divided two or three times a year. Always take into account how long it has taken for your prized hosta to get as big as it has before going and cutting it into hundreds of tiny pieces.

When dividing you can take as little as one or two buds off, cut completely in half or cut the whole plant in hundreds of pieces. The larger the amount divided the higher chance of survival.

How big does my hosta have to be before I divide it?

Any hosta that has more than two eyes (buds/stems) can be divided. This however does not mean the division will always be successful. The bigger the division the more likely it will survive. Smaller or slower growing varieties need to be divided with care, fast growing varieties can be cut to pieces and still survive without too many failing.

General Hosta Information

The genus, Hosta, represents a wide variety of herbaceous, perennial plants. Hosta plants are popular plants amongst gardeners due to their lovely, variegated leaves, their low maintenance requirements, and their shade tolerance. Since Hosta have a vast array of different color combinations on their leaves, many homeowners will add these plants to their gardens in order to enhance aesthetics. Due to this fact, Hosta plants have become some of the most highly demanded plants on the market.

Common Methods of Propagation

There are a few different ways in which the members of the Hosta genus can be propagated. Some of the common methods used to propagate these plants include division, cuttings, seeds, and tissue culture. Of these methods, the most commonly used method of propagation is via division.

Division (shown at left) is a process in which the healthy parent plant is uprooted during the spring and then daughter plants are taken from the mother. In the genus Hosta, the mother plant develops a very substantial root system which has the capability of being divided into multiple daughter plants. These divided daughter plants can then be transplanted as a form of propagation. Due to the simplicity and relatively small equipment requirement, division has become the most commonly used method for propagating these plants.

Even though division is the most common, it has limitations. Division can only be done at a certain time of the year (which is during the spring) so that the plant has a long enough growing season to establish roots. Also, since the root size of the mother plant is not infinite, the mother plant is only able to produce a limited amount of offspring. Therefore, division falls short in producing enough plants to satisfy the market demand.

Another less common method for propagating Hosta plants is via root cuttings (shown below). In order to do a successful root cutting, you must uproot the mother plant during the spring and then proceed to take cuttings from its root system. Once you have the number of cuttings that you would like to propagate, you will need to induce injury on the roots in order to get proper callus formation and thus the formation of other necessary plant tissue like shoots and leaves. This method is not nearly as successful as division for two reasons: 1. Hosta mature very slowly so it is not commercially efficient to propagate a large amount of these plants via root cuttings. 2. The necessary induced injury of the root in order to promote callus growth could introduce diseases which hinders the success propagation.

Root Cutting Example

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One of the other methods that can be used to propagate Hosta is propagation via seeds. Again, this method is not used commercially because of the length of time that it takes these plants to mature. Hosta are typically only propagated via seeds by plant breeders who are attempting to develop new cultivars with different phenotypes.

The final way that these plants are propagated is via tissue culture (shown below).

Of the methods mentioned, tissue culture is the newest method for propagating plants and therefore has not been as extensively used as the division. However, over the years technology has advanced making tissue culture more and more prevalent. The main reasons in which tissue culture is the second most common way to propagate Hosta today is because it increases the total amount of potential daughter plants as compared to the

other methods. Propagating these plants using tissue culture allows propagators to produce about twelve times more daughter plants than that of division. For this reason, commercial propagators typically prefer to use this method in order to satisfy the demand for these plants. The steps for propagating a Hosta via tissue culture will be described in further detail throughout the rest of the webpage.

Propagation of Hosta via Tissue Culture

The most important thing to remember when propagating plants via tissue culture is that you must keep EVERYTHING as sanitary as possible in order to limit the potential for pathogens to cause negative results. To begin, the following is a list of items that you will need in order to successfully propagate a plant via tissue culture. Keep in mind that even though some of these items are expensive and sophisticated, there are plenty of household items that be used to replace such items that make tissue culture possible for the home gardener. All that you need to do is use your imagination and remember that sanitation is KEY.

You will need:

  • A healthy mother plant as a source of plant tissue
  • Petri dish(es) (plastic kitchen containers will also work)
  • Tweezers/forceps
  • Sharp knife
  • Rubber gloves
  • Sanitation equipment (alcohol and flame, Bacti-Cinerator, bleach, autoclave, pressure cooker)
  • Plastic wrap
  • Transfer hood/sanitized work space (a sanitized cardboard box will work)
    • The key is to keep airborne spores away from the work area
  • Nutrients and hormones for the plant (carbohydrates, vitamins, hormones)

Step 1: Sanitize Your Equipment and Tools

  • You must sanitize more or less everything that is mentioned in the materials section above (anything that will be used within the work area and/or come in contact with the plants and petri dishes)
  • This can be achieved by using any of the sanitation equipment mentioned above
  • If using bleach, use a concentration of ten parts water to one part bleach and allow tools and materials to soak for about fifteen minutes
  • Be sure to wash your hands and wear rubber gloves when you are in the work area

Step 2: Prepare the Media

  • Mix clean water with vitamins, plant hormones/PGR’s (auxins, cytokinins, gibberellic acids), carbohydrates (table sugar), and gelling agents (agar) to the proper volume of media that you deem necessary for your containers
  • Adjust the pH of the media to about 5.7 by adding small amounts of HCl or NaOH at a time
  • Stir and heat the solution for about five minutes to melt the agar
  • Pour the solution into your propagation containers and place them into an autoclave (or pressure cooker)
  • Remove from autoclave and keep covered/sanitized until ready to be used

Step 3: Prepare the Vegetation for Propagation

  • Daughter plants can be grown from various parts of the mother plant, but we will focus on propagating new Hosta from leaf cuttings. The technique used for propagating other parts of the mother plant is very similar to the technique that is used for leaves.
  • Select a healthy leaf from the mother plant and use a sharp knife to remove it from the mother plant
  • Take the leaf and soak it in the 10:1 bleach solution for fifteen minutes to disinfest the leaf. Be sure that the entire leaf comes in contact with the solution for the full fifteen minutes.
  • Remove the leaf from the bleach solution and dip it into a series of three, separate containers filled with pure water in order to remove the bleach from the leaf.
  • Using a sterilize knife and tweezers, proceed to cut the leaf into smaller pieces
    • The pieces can be any shape, just make sure that they are around a centimeter in diameter
    • A good cutting should look something like (a) or (b) in the photo below

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  • Using the tweezers, take the one centimeter pieces of leaf and place them into the containers that contain the media you have prepared
    • The agar will have caused the media to become a gel. Simply place the leaves on top of the gel making sure that one of the sides of the leaves is touching the gel but being sure that the leaves are not completely submerged in the gel (as shown in the photo below)

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  • Place the lid on the containers and wrap with Para film or plastic wrap to ensure that pathogens are kept out of the culture

Step 4: Move Containers into the Proper Tissue Culture Environment

  • The environmental conditions for proper growth in tissue culture is similar to the normal environmental growing conditions for a plant in an ex vitro system
  • Place the containers under artificial light for a photoperiod that is similar to the photoperiod of the summer days in your area
  • Make sure that the temperature of the room is around the optimal growing temperature which is room temperature for tissue culture
  • Check to make sure that there are no sources of harmful gases (like ethylene) near the plants

Step 5: Wait for Root Formation

  • Check the containers every day or every other day to evaluate the health of the cultures
  • Any containers that appear to have diseases or pathogens should be removed in order to limit the potential for cross-contamination into the other containers
  • After healthy roots and shoots have begun to form to a satisfactory level, you may either subculture the plants to develop even more daughter plants or you can remove the plants from in vitro growth and place in an ex vitro system

Step 6: Hardening Off Daughter Plants

  • Since the daughter plants have been kept in vitro, they are not used to normal atmospheric conditions and therefore they must be hardened off in order to become acclimated to normal growing conditions
  • To successfully harden off the plants, you need to take things slowly
  • Start by removing the cap to reduce the humidity for a few days
  • Once they have become acclimated to the change in humidity, you can transplant the cultures into regular growing media and place them in a greenhouse and exercise normal greenhouse care (routine watering, humidity control, disease control, etc.)
  • If you have done the following steps correctly, the transplants will survive and thrive in the greenhouse environment
  • After you see that the plants are well-established in the greenhouse environment, you can plant the Hosta outdoors in your garden
  • Congratulations! You have successfully propagated a Hosta via tissue culture!

Sources

Dunwell, Winston. “Hosta Propagation.” University of Kentucky, 1999. Web. 22 Oct. 2015.

Mortko, Rob. “Growing Hosta.” Growing Hosta. 2015. Web. 22 Oct. 2015.

How to plant bare-root perennials

Have you ever ordered a bunch of plants and then been surprised (and maybe a little disappointed) when you opened the box? You had visions of huge, blooming plants, and all you got were plastic bags with a few roots in peat moss. It’s easy to overlook the words “shipped bare root” in the tiny type when you’re caught up in the catalog pictures. Well, bare root isn’t a bad thing. It’s an economical way to buy plants and you can often find varieties that are hard to find locally. Here’s how to get them off to a great start.

Scout for problems

Check things over to make sure your new plants are in good shape so they can get a strong start. If you do happen to notice any problems, be sure to take photos and contact the nursery for a replacement. The daylily in the photo above had a few broken roots, which isn’t a big deal — just prune them off. Leaving a dead root to rot on the plant offers an easy place for disease to take hold. Rotten or dessicated roots can be a more serious. Any plant that looks completely dry and brittle has dried out so much it won’t recover so go ahead and toss it on the compost pile. Soft, mushy, sometimes smelly, roots have rot. That plant needs to be thrown in the trash or burned. Compost piles don’t get hot enough to kill the fungus that causes the disease, and you shouldn’t bury the plant because that might spread the problem, too.

Prepare for planting

Once you’ve looked over your new bare root plants, soak them in a bucket of water for an hour as the photo above shows. Add a few drops of fish emulsion fertilizer to give plants a boost to start growing.

How to plant bare-root perennials in pots

The most common reason for potting up bare-root plants is because the weather and the soil are still too cold for them to go outside. But you might also want to baby an expensive or temperamental plant by closely controlling the moisture and light levels. Or maybe it’s summer already and hot temperatures would be a big shock for your young plant. Growing it in a pot in a cool, shady spot for a while will help ensure its success. Here’s how to get bare root plants going in a nursery pot.

GET A GOOD MIX Make sure to use a soilless potting mix, not soil. Most mixes are made of sphagnum, peat and perlite, which drain well. While getting too dry is a problem for packaged plants, rotting is the biggest concern once they’re planted. So at this point, it’s better to have dry potting mix instead of premoistening it.

POT THEM UP While your plant is soaking in the bucket, get a nursery pot that’s a little larger than the root mass so there’s room for roots to grow. Choose a pot that’s big enough that you don’t have to bend the roots to get it to fit. Now fill the pot part way with the potting mix and tap the bottom on your work surface to settle it. Then add the plant, fill the pot the rest of the way and tap it again to settle. For plants that don’t have foliage position the crown (that’s the spot where the roots and green growth come together) about an inch below the surface of the potting mix as the illustration above shows. If it’s set too low, water can pool there and the crown will rot. Make sure any foliage that has sprouted is showing above the potting mix.

Don’t worry about yellow leaves like these. That’s normal — the plant just didn’t get enough light in storage or shipping. It will green up in a week or so. Water your new perennial until water runs through the holes in the bottom of the pot. To firm the mix around the roots, wait 20 minutes and water again. Use a watering can with a rose for a gentle flow that doesn’t wash the soil away. Remember, you don’t want the plant to rot so there’s no need to water again until you see green growth sprouting.

LET THEM GROW Once your plant is potted up, it needs a place to grow. In spring, if temperatures are still around freezing, keep it inside where it’s cool, 60 degrees F or so. Avoid air vents that can dry out potting mix and foliage too quickly. A sunny windowsill should provide enough light, even if there aren’t any leaves yet. Usually within a couple of weeks you’ll see new green growth, so you can start watering with a weekly dose of fish fertilizer or a half-strength solution of balanced liquid fertilizer. When there’s vigorous growth on top, your plant is ready to go into the ground.

Once the soil is warm and dry enough to work, your plant can go outside. Give it a sheltered shady spot to start with so sun and wind don’t damage the new leaves.

Plant bare-root perennials in the ground

Tough plants like daylilies and hostas won’t mind if you take them from the box and plant them in the ground, as long as all chance of frost is past. The daylily in the photo below is going directly in the garden. This process is similar to potting up, but there are a few differences:

PREPARE THE SOIL Clean up and soak the plants, just as you do before potting up. While the plants are soaking, dig a hole a little wider than the root mass of the plant you’re putting in the ground. Make a mound of soil in the center of the hole as the photo above shows. That gives the plant support and a place to spread out its roots. Water the empty hole before you plant to help settle the soil.

PLANT THE PERENNIAL Place the plant on the mound and make sure the crown is even with the soil’s surface. If the crown is too low add more soil to the mound to avoid rot, check the plants position again and refill the hole with soil.

Water gently so the soil isn’t washed away.

TAKE GOOD CARE OF YOUR PERENNIAL Keep your new perennial going strong by watering it about once a week if it doesn’t rain — more often if it’s hot. Even sun perennials do better with a little shelter from the hottest part of the day for a few weeks until they get established. Place a laundry basket over the top of the plant for a few hours in mid- to late afternoon each day. Once new growth starts, scratch compost into the soil a few inches out from the crown to feed the plant.

Pests aren’t any more of a problem than they are with other plants. So keep an eye out and treat accordingly. Some plants, such as coral bells or this daylily, will take right off. Others, such as hostas, may sit for a while. They’re just slower to get established, so be patient. It won’t be long, though, and those humble brown roots will be great looking new plants.

For more on how to plant perennials, read our article How to plant perennials in four simple steps.

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