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Search Results for ' Vegetative propagation'

PAL Questions: 13 - Garden Tools: 3 - Recommended Websites: 1

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Keywords: Vegetative propagation, Gunnera

PAL Question:

When and how do I divide my Gunnera?

View Answer:

"Divide large types before growth starts into single crowns in midspring." (Source: American Horticultural Society Plant Propagation, ed. by A. Toogood, 1999, p. 198)

"Many gunneras are huge and so are impossible to dig up and divide in the conventional sense. For propagation, cut pieces from the edge of the clump. Pot up in a large pot and in a fibrous medium and keep moist." (Source: The Complete Book of Plant Propagation, ed. by C. Heuser, 1997, p. 40)

The sources I looked at indicate that you should divide your Gunnera in April or May. Because of the size of the plant, it may be impractical to divide the rootball. You can use a spade or pitchfork to cut sections from the main clump, and then plant those divisions in pots, keeping them moist. Gunnera is a tough plant, and should take well to this kind of division, as long as there is adequate moisture.

Should you need to protect your Gunnera over the winter months, you can cut the leaves and use them like a tent to protect the crown of the plant during the coldest months.

Season Spring
Date 2006-03-03
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Keywords: Perennials--Care and maintenance, Vegetative propagation, Iris

PAL Question:

When is the best time to divide and transplant Irises? I have Japanese, bearded and yellow flag (I think) irises.

View Answer:

Rhizomatous irises (the kinds you have) are best divided in midsummer:

“Lift rhizomatous kinds, such as bearded iris, in midsummer and cut rhizomes into sections, each with roots and a fan of leaves; replant, with tops barely covered, 6 inches apart. Flowers will be sparse the next year, but good thereafter…”
(Source: American Horticultural Society Plant Propagation, ed. by A. Toogood, 1999, p. 202)

“The optimum time…..is six weeks after flowering. This is usually in midsummer, allowing time for the new rhizome to become established and make sufficient growth to produce fans to flower the following year. New roots that began growing immediately after flowering will then be strong enough to help anchor the new plants. Early spring is another suitable time, just as the other main period of root growth is about to start, but flowering may be forfeited, and if flowers are produced the stems will almost certainly need staking….Bearded iris cultivars are tough, and if the rhizome is large they can survive out of soil for many weeks. This is not an ideal situation, but it makes transport of the plants easy.”
(Source: The Gardener’s Guide to Growing Irises, by G. Stebbings, 1997, p. 93)

Good instructions can be found in these articles:
July, August Time to Divide Iris
Garden Experiences: Dividing Bearded Iris

Season Summer
Date 2008-01-10
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Keywords: Phormium, Vegetative propagation, New Zealand plants

PAL Question:

Can I divide New Zealand flax without killing it? When should I do it? My adult plant, about three years old, has two very healthy looking youngsters that I would like to move.

View Answer:

The best time to divide Phormium is spring, according to American Horticultural Society's Plant Propagation (DK Publishing, 1999), but what you are describing are new offsets, so you will not be splitting the entire crown of the plant, but instead separating them from the parent plant. Wear gloves when working with Phormium. You may be able to use two garden forks to separate the youngsters from the parent.

Season All Season
Date 2006-10-26
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Keywords: Vegetative propagation, Nandina domestica

PAL Question:

I have a Nandina (heavenly plum blossom) that is getting really top heavy and I need to find out how to divide it or cut it back and root the cuttings. I've been reading up on it and there is very little information about propagating them.

View Answer:

The book American Horticultural Society Plant Propagation by Alan Toogood (1999) recommends taking nodal greenwood (similar to softwood) cuttings in the summer. The shrub can also be propagated by division but this is recommended in the early spring and not in summer due to the increased risk of wilting and scorching.

Rainy Side Gardeners in the Pacific Northwest notes that fresh seed (as soon as it is ripe) can be germinated in six to eight weeks. Old seed may take up to two years to germinate. Semi-ripe cuttings can be rooted in the summer.

As for pruning the Nandina, the American Horticultural Society Pruning and Training: A Fully Illustrated Plant-by-Plant Manual by Christopher Brickell and David Joyce (1996) suggests that plants can usually be renovated by cutting back old canes to ground level in the early spring when the older leaves have turned from red to green. Rainy Side Gardeners suggest cutting the oldest canes down to the ground, discouraging the shrub from getting top heavy and falling over. The pruning will keep it growing a denser growth lower down on the shrub.

A Practical Guide to Pruning: How and When to Prune for Better Shrubs, Trees, Fruits and Climbers by Peter McHoy (1993) suggests cutting one out of every three canes to the ground. His recommendation is not to do this each year.

Paghat's Garden (a website maintained by a local gardener) had this to say:

"Nandina thrives in considerable shade, but has a tendency to become leafless underneath unless it can get sunlight around the lower part of the plant. Before I transplanted this one, it was in a lot of shade, & needed to be staked because it became top-heavy. This did not necessarily harm its looks, because the species' tendency to lose leaves at the bottom gives it the appearance of a miniature tree with long trunk, & I used the "empty" space around its base for small ferns. But when transplanted to a sunnier garden, it became more broadly bushy & the trunk became stronger, no longer needing to be staked."

Season All Season
Date 2007-07-16
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Keywords: Vegetative propagation, Lilium (Lily family), Bulbs

PAL Question:

I have a question about what is the best time of year to transplant and divide Asiatic lily bulbs? Is it fairly easy to identify where the bulb should be divided? Also, someone told me to use a rooting solution on the divided bulbs. Is this necessary? Is late October too late in the fall to divide them?

View Answer:

Most sources say to divide lilies in the fall. You do not need to use a rooting solution on the divided bulbs. Sunset’s Western Garden Book (2001) says the following: "If clumps become too large and crowded, dig, divide and transplant them in spring or fall. If you’re careful, you can lift lily clumps at any time, even when they are in bloom."

One rationale for lifting them when in bloom is provided in an article from the Wisconsin Regional Lily Society, no longer available online, but excerpted here:

"After three successive years of making this futile pact, I finally concluded that books were wrong! Fall isn't the time to transplant lilies. It's a job best done in mid-summer when they're in full bloom. This eliminates most of the guess work, since at this point, the plants are at their maximum height, making it nearly impossible to make the mistake of planting the tall ones to the front of the border, the short ones at the back. It also affords a crystal-clear picture of concurrent bloomers. In fall, no matter how carefully one does the job, when digging dormant bulbs at least one bold orange always manages to get itself placed directly beside the brightest pink. The clashing colors burn themselves into your retinas nearly as well as flashbulbs-blink quickly and the image reappears!

"The maximum size of the plants in mid-summer is another advantage. When autumnal plants have shrunk to a mere fraction of their former selves, it's too easy to misjudge your space placement. Who hasn't heard the disheartening 'crunch' of a spade slicing through the most expensive bulb in the bed? How it knows the price, I'll never know.

"Spring is the only time I'd actually refrain from moving lilies. The delicate new shoot is easily broken, and once gone, the poor bulb has only two options: It will either die or spend an entire year below ground, depleting its energy reserves as it forms a new shoot for the following spring. All the while it's caught in a perilous game of Russian roulette. Without aboveground parts to warn of its existence, it can never quite be sure when a spade might suddenly come slicing down. Crunch! -The second most expensive bulb gone?

"Certainly no plant will be thrilled at being dug up and moved in full flower, but if it's kept well watered and blooms are removed, almost any perennial will have recovered fully by the following season. One of the best gardeners I know says that the best time to move any perennial is when you have the time!"

Season Fall
Date 2007-10-12
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Keywords: Vegetative propagation, Lilium (Lily family)

PAL Question:

My Easter lily died, and as I was removing some of the soil I saw a small green bulb (less than an inch long). The tag that came with it said they can grow year round, and I live in Florida where it always stays warm enough. I decided I wanted to try to salvage that bulb and regrow it. Can I safely remove that bulb from the stem of that dying plant and replant it?

I also have recently planted some small Asiatic lilies (which are growing like mad, I planted the bulbs less than a month ago and they are already over 6 inches tall!) and want to be able to do the same when they die. I hope you can help me out, I love lilies and want to be able to keep these going and then add more and more. Thank you!

View Answer:

The Complete Book of Plant Propagation (edited by Charles Heuser; Taunton Press, 1997) gives these instructions for growing on "stem bulblets" like what you see on your Easter lily (Lilium longiflorum):
"Pick off the bulblets carefully, to avoid damage to any small roots that may already have formed. Plant bulblets at twice their own depth in a prepared pot of medium [potting soil], and mulch with a layer of sand. ...Grow on in a cold frame [I guess that would be outdoors for you, but shaded]. The following fall, pot up individual bulbs separately, or if growth has been vigorous, set ... in the flowering site. ...will take 2-5 years to flower."

The same process should work for your Asiatic lilies (Lilium hybrids), if you have stem bulblets there, or you could try "scaling." Scaling involves breaking a bulb into individual scales, throwing out any soft or wrinkly ones, and bagging them up in a sand/peat mixture (inflate the bag with air) at 61-77 degrees Fahrenheit for 4-12 weeks. Each scale should sprout bulblets, which you can treat like stem bulblets, except leave them attached to their scale (as long as it is firm) and don't bury them so deeply while the bulblets are small: 1/4 of sand over the scale bulblets is enough.

Season All Season
Date 2008-05-21
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Keywords: Taxus baccata, Vegetative propagation, Conifers--Propagation

PAL Question:

I planted a Taxus baccata fastigiata roughly 10 years ago and it grew to about 1.5m. Unfortunately it was cut down by mistake. Is there any way I could take a cutting from the tree or some way to preserve any part of it, as it holds great sentimental value.

View Answer:

According to The Complete Book of Plant Propagation, edited by Charles Heuser (Newtown, CT: Taunton Press, 1997), your yew can be propagated by cuttings, but it is recommended that the cuttings be taken in fall. It's worth a try to take some now, though, since the tree is already cut. You want upward-growing, semi-ripe cuttings (that is, there should be some bark at the base and some green stem at the tip), and they should be pulled off with a downward motion so that you get a "heel" of bark from the main shoot. Treat them with rooting hormone and place in a pot somewhere where it can remain cool and moist for several months. Take plenty of cuttings to increase your chance that at least one will survive.

American Horticultural Society's Plant Propagation, edited by Alan Toogood (New York: DK Publishing, 1999), has more specific suggestions. They suggest a 4-6 inch cutting from 1-3 year old wood that is still green at the base.

If your yew made seeds, you might try planting them, but it takes a long time for them to germinate and grow from seed. To grow from seed, the AHS Plant Propagation recommends mixing the seeds with damp peat or sand and keeping them at about 68 degrees for 4-6 months, then at 34 degrees for 1 month before planting. If the seeds germinate in late summer, though, they won't be ready to winter outdoors that year. For this reason, the AHS also suggests simply sowing the seeds outdoors and waiting for germination in 1-2 years. If you do this, be careful not to lose your sown seeds while waiting for them to grow!

Season All Season
Date 2008-06-11
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Keywords: Vegetative propagation, Transplanting, Hydrangea

PAL Question:

I have a very large hydrangea that has been in the ground at least 15 years. I'd like to move it, and have heard that it can be divided into several bushes. Are there any special details I should consider when performing this task?

View Answer:

I found a reference to the technique you describe in Hydrangeas: A Gardener's Guide by Toni Lawson-Hall and Brian Rothera: "DIVISION. Sometimes, when moving a large H. macrophylla cultivar, the plant falls apart during the operation. It has been found that, provided each section has good roots, planting the separate pieces is totally successful." This is similar to the process of layering, where branches are nicked and then pinned down into the soil to allow roots to form, and then severed from the parent plant with a sharp shovel six months to a year later. The small plants will be genetically identical to the original plant.

Season All Season
Date 2009-03-07
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Keywords: Ophiopogon planiscarpus 'Nigrescens', Vegetative propagation, Seeds

PAL Question:

Last year, I collected and propagated seed from my black mondo grass. I now have about a hundred healthy starts which are green in color, with leaves thicker than those of the parent black mondo plants. Is this just their immature color, or do they not come true from seed?

View Answer:

Most of the resources I consulted recommend propagating Ophiopogon planiscapus 'Nigrescens' by division of clumps in fall or late winter, but The Plantfinder's Guide to Ornamental Grasses by Roger Grounds (Timber Press, 1998) says the following:
"The flowers are mauve, but the berries are black, and if sown will produce about one-third black seedlings, the rest being green."

If all of your plants came up green, I would guess they will stay that color (in other words, they must have reverted to the species, Ophiopogon planiscapus, which has wider green leaves).

Season All Season
Date 2009-03-28
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Keywords: Vegetative propagation, Dierama, Propagation

PAL Question:

Could you provide some information on the propagation and division of Dierama (not sure if the species I have is D. pendulum or D. pulcherrimum. It has pink flowers and is also known as Angel's Fishing Rod)? The clump has gotten large and I'd like to see if I can divide it now in fall.

View Answer:

The Royal Horticultural Society has an advice page on how to divide and propagate Dierama.
Excerpt:
Named cultivars can be propagated by division in spring or immediately after flowering; but this should only be undertaken occasionally as plants are slow to re-establish. Plants grow from corms that build up year by year into chains, similar to Crocosmia.

  • Lift plants and separate corms, reducing the foliage by half with secateurs.
  • Take care not to damage the brittle, fleshy roots.
  • Divisions take one to two years to flower freely again.
  • For an answer from local experts, I consulted Perennials: The Gardener's Reference by Carter, Becker, and Lilly (Timber Press, 2007). The authors say that "it's best not to transplant, divide, or groom in the fall." Instead, if you must divide, do so in April or May and include several corms in each clump. You can also sow ripe seed at that time. Seed may be harvested by shaking the stems.

    Season All Season
    Date 2009-11-07
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    Keywords: Zantedeschia aethiopica, Vegetative propagation

    PAL Question:

    Can I divide my Calla lily? When should I do this?

    View Answer:

    According to Sunset Western Garden Book (2007), Calla lily (Zantedeschia) should only be divided if it shows signs of decline. The Royal Horticultural Society suggests dividing in spring, if needed:
    "Propagate by division, in spring. Small rhizomes that have been overwintered in pots under cover can literally be cut up into sections, each with a visible bud. Large overwintered clumps in the garden can be divided in the same way as other perennials, by lifting the plant before there is much top growth, and chopping through the roots with a spade and dividing into smaller sections."

    Season All Season
    Date 2010-03-25
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    Keywords: Festuca, Vegetative propagation

    PAL Question:

    I have grown Festuca glauca for many years. While they have an annoying propensity to seed themselves everywhere, I have never seen Festuca send off many little plantlets, as one of mine is currently doing. Of all the Festuca that I grew, this one got the least amount of sun, and was near other taller plants, and it was also probably exposed to the most humidity.

    Is this really a sign of the Apocalypse, or just another result of a crappy summer?

    View Answer:

    We had lots of theories put forth by library staff and professional gardeners, but according to plant ecophysiology professor Soo-Hyung Kim, your plant is demonstrating vivipary (or in the case of plants like Festuca, which are in the family Poaceae, pseudovivipary). I found information about vivipary in an article by Thomas Elmqvist and Paul Alan Cox, published in Oikos, vol. 77, no. 1, pp. 3-9, October 1996.:
    "Vivipary in flowering plants is defined as the precocious and continuous growth of the offspring when still attached to the maternal parent. Two main types, true vivipary (involving sexually produced offspring) and pseudovivipary (asexual offspring), may be identified. Vivipary has been described from slightly less than a hundred different species of flowering plants, of which we classify approximately 50% as having true vivipary, with the remaining species being pseudoviviparous."

    There is additional information in Flora of North America, vol. 24, p.392:
    "Under adverse conditions, many species [of Festuca] may proliferate vegetatively, where leafy bulbils or shoots form in place of some or all spikelets. Some populations of Festuca are largely (or completely) sterile, reproducing almost entirely through such bulbils, a process termed pseudovivipary. Pseudoviviparous plants may be common or even abundant in certain areas and habitats."

    Some scientists (cited in Elmqvist and Cox article) suggest that pseudovivipary is an evolutionary response to a short growing season (as in arctic, alpine, or arid areas). Perhaps your plant is in its own microhabitat!

    Season All Season
    Date 2010-10-01
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    Keywords: Perennials--Care and maintenance, Vegetative propagation

    PAL Question:

    When and how do I divide Tradescantia?

    View Answer:

    Divide in spring. "Cut away excess foliage, keep divisions moist and sheltered." (Source: American Horticultural Society Plant Propagation, ed. by Alan Toogood, 1999, p. 148, 210).

    Season Spring
    Date 2011-07-21
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    Keywords: Vegetative propagation, Verbascum, Rudbeckia, Phlox, Papaver

    Garden Tool:

    Take root cuttings in autumn, once rain has arrived, to make new plants of many popular perennials like oriental poppies, verbascum, garden phlox and black-eyed susans. The September/October 2004 issue of Horticulture Magazine gives clear instruction on this easy propagation technique, and suggests many other suitable plants. In a nutshell:

    1. lift the plant to be propagated with a garden fork
    2. shake off soil to expose the roots
    3. cut out a few roots that are about the thickness of a pencil, noting the "top" of the root (closest to the plant)
    4. cut the root into 2 inch pieces
    5. insert the pieces into a small container of potting soil, with the top end just under the surface
    6. keep the container moist, not wet, and inside in bright light until new growth appears
    7. transplant into individual pots when growth is a couple of inches tall

    Season: All Season
    Date: 2007-04-03
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    Keywords: Vegetative propagation, Transplanting

    Garden Tool:

    Early fall is that magic season in the garden when a good soaking rain and warm soil trigger a flush of new growth in perennials and some shrubs before cold temperatures slows everything down. This explains why now is an ideal time to transplant, divide and otherwise shuffle around your plants. For an illustrated essay on techniques and timing of dividing perennials go to: Clemson University Extension.

    Season: Fall
    Date: 2007-03-26
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    Keywords: Plant and garden societies, Vegetative propagation, Iris

    Garden Tool:

    August is a good time to lift and divide your Bearded Iris, but don't touch your Pacific Coast Native Iris until the rains return in fall. To learn more about the joys of growing this "Flower of the Rainbow" go to the American Iris Society's website.

    The King County Iris Society holds lectures and events throughout the year and publishes a monthly newsletter. Their annual rhizome sale is September 13 and 14 at Crossroads Mall 15600 NE 8th St, Bellevue. To join the society send $10.00 to KCIS Membership Chair, PO Box 95538, Seattle, WA 98145-2538. Online at www.kcis.org.

    Season: Summer
    Date: 2007-04-03
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June 24 2013 12:55:25