Transplanting Yuccas

I have a number of large Yucca plants in my yard that I would like to dig up and transplant. I am not entirely familiar with this type of plant, but have noticed that, likely due to the age of these plants, several trunks have sprouted from the mother plant and have begun growing as what appear to be separate plants. However, these extensions are easily lifted from the ground and show no evidence of independent root development. Can I cut the new plants from the original plant and get these to take root elsewhere?

Following is some information that may help you in transplanting your Yuccas.

TRANSPLANTING

From Agaves, Yuccas and Related Plants: A Gardener’s Guide by Mary & Gary Irish (2000, pages 65-68):
“In mild winter climates that have hot summers, particularly hot and dry summers, fall planting is best, so that root systems establish through the mild winter before the onset of the stressful summer season. If planted in early spring, plants must be carefully watered and shaded from the sun during the summer to prevent sunburn and debilitating heat stress. When planting agaves [or yuccas], regardless of the soil type, raise the center of the hole slightly, just an inch or so, and plant the center of the plant at the top. The crown of the agave [or yucca] particularly is susceptible to infections, and when the soil inevitably subsides after planting, the crown can sink below the soil line. The practice of raising the center of the planting hole slightly is helpful in all the stemless members of both families to prevent crown rots.

“For all plants, begin by digging a shallow hole no more than the depth of the root system. Backfill the planting hole without soil amendments or with a very small amount of compost. Tamp the soil lightly as it is backfilled to prevent excessive settling later…

“Moving mature arborescent plants, such as some members of Beaucarnea, Furcraea, Nolina or Yucca, is more difficult. These large plants are sensitive to root and stem disturbance, and wounds of the basal growing platform in Yucca can introduce a host of infectious agents into the plant. If possible, it is much more advisable to move such plants when they are young and nearly stemless.”

PLANTING TOES AND SUCKERS

From American Horticultural Society Plant Propagation by Alan Toogood (1999, p. 145)

“In spring, carefully uncover the base of a sucker. Cut it off at the base where it joins the parent rhizome. Dust the wounds with fungicide. Pot the sucker singly in a free-draining medium, such as equal parts soilless potting mix and fine grit. Keep at 70 degrees F until rooted (12 weeks).”

Propagation, Rooting, Transplanting, Yucca

Spread of Ranunculus ficaria

Can you tell me about the spread of Ranunculus ficaria ‘Green Petal’?

The Royal Horticultural Society’s A-Z Encyclopedia of Garden Plants (ed. Christopher Brickell; DK Publishing, 1996) indicates that Ranunculus ficaria (now known as Ficaria verna) spreads a foot or more, but the following information, from a local gardener (Paghat) who grows several cultivars of this plant, suggests that “more” may be quite a bit more. Excerpt: Due to their being potentially invasive, we placed them where it would not matter, but might even be rather nice, if they spread a great deal.

The species is considered invasive, as these sites indicate:

From the Urban Ecology Center

From the USDA site.

It is possible the cultivar is less invasive than the species, but I would certainly keep an eye on it.

Invasive plants, Ranunculus

UW cherry tree blossoms

I would like to know when most of the beautiful flowering trees will be in bloom on the University of Washington campus this spring? I would like to bring a tour group to see them.

Typical bloom time for the Yoshino cherry trees (Prunus x yedoensis) in the Quad is mid- to late-March, but timing is weather-dependent. You can check the UW Cherry Cam, which they update each spring: https://www.washington.edu/video/campus-webcams/

This article shows the stages of flower development and provides additional detail about the factors affecting bloom time. Here is another article about research into predicting bloom time.

Excerpt:

“The timing for peak bloom — meaning 70% of buds have emerged — varies each year based on weather conditions that the developing buds are exposed to in January, February and March.

“”‘In order to reach peak bloom, buds need to accumulate a certain number of both cold and warm days, known as ‘growing degree days,’ said Marlee Theil, a UW graduate student in the School of Environmental and Forest Sciences.”

Flowering cherries, Flowering trees, Garden tours, Prunus, University of Washington

Camellia winter protection

How can I protect my camellia shrubs from very low temperatures?

The website of the International Camellia Society has a discussion of camellias and their cold tolerance, indicating that most spring-blooming Camellia japonica and fall-blooming Camellia sasanqua cultivars will survive a Washington, D.C. winter (zone 7, compared to our zone 8), but there is some concern about extreme cold and drying winds, and sudden drops in temperature (see excerpt below on winter protection, from the University of Georgia Cooperative Extension Service):

Winter Protection

Covering a camellia plant provides frost protection but does little good in a severe freeze. If plants are covered with cloth, plastic or paper, prop up the cover so that it does not touch the buds. Put the cover on after the sun goes down and remove it before mid-morning the next day.

There are additional approaches to providing winter protection against plant damage. Maintain good soil moisture, especially just before freezes. Maintain adequate nutrition by following current fertilizer recommendations. Plant in locations that provide moderate winter shade. Select varieties with good winter hardiness.

The article below from the North Carolina State University Extension has a good general discussion of winter protection for camellias.

Camellia, Cold protection of plants, Frost

Blooming bamboo

I have a bamboo, Fargesia nitida, ‘Blue Fountain Bamboo,’ that seems to be blooming this year. Are other specimens of this species blooming in Seattle this year? (I heard a rumor that blooming is synchronized among bamboo plants.) Will it die? Will it produce seeds without a “partner”? I am curious since blooming bamboo isn’t something you see every year in Seattle.

My best suggestion is to look at specialist nurseries in your area, or contact your local Parks Department to see if there are any public gardens where you can view other specimens of Fargesia.

As far as the question of whether your plant will die after flowering, here is an article abstract about this subject (which does suggest that the plant will die, but also indicates that this is a time of opportunity to propagate the bamboo).

I also found some general information about propagating bamboo from this archived page from American Bamboo Society:

Q. How do I propagate bamboo?

Bamboo is usually propagated by digging up part of a clump of existing bamboo and moving it elsewhere. The vast majority of propagating is done that way and it results in most plants of most varieties in the U.S. being clones. If you divide a bamboo plant and put it in a new location, it usually doesn’t do much for the first few growing seasons. The first two years it puts out roots in its new location and usually by the third year it starts putting out larger culms. By the fourth or fifth years it’s putting out culms as large as that plant ever will in that location, with that much sun and that much water in that kind of soil.

Bamboo flowers only rarely, (sometimes there’s more than a person’s lifetime between flowerings) and when it does, it takes so much energy from the plant it often dies. People try various things to save them, like cutting back the culms and fertilizing generously, and sometimes that works.

It can also be propagated via germ plasm. A small number of cells are taken from some part of the plant and grown in glass dishes. Ordinary people don’t do this, of course.
Finally, with some tropical species, it’s possible to bend a culm in an existing clump of bamboo down to the ground, stake it and cover it partially with soil. Be sure to cover several of the nodes of the culm, as that’s where it will form roots. Don’t let the soil dry out completely.

According the Plants for a Future database, Fargesia nitida flowers are hermaphroditic, and are pollinated by wind.

I found some anecdotal information about propagating Fargesia nitida from seed on the University of British Columbia’s garden forum, shown below:
You can harvest the seed individually by hand. But it seems the best way to know that it is ripe is to allow it to fall to the ground, as they only fall when they are ripe. In order to not leave things to chance, it is recommended that a piece of cloth or a tarpaulin be placed on the ground, and the seed bearing culm be shaken. The best germination rate is when the seeds are sown fresh.

Bamboo, Fargesia, Propagation

Germinating Gaultheria procumbens

What specific requirements are needed to germinate Gaultheria procumbens in soilless media?

Any tips on seed stratification, cultural advice, etc., etc.?

The information below comes from the website of Plants for a Future:

“The seed requires a period of cold stratification. Pre-chill for 4-10 weeks and then surface sow in a lime-free compost in a shady part of the greenhouse and keep the compost moist. The seed usually germinates well, usually within 1- 2 months at 20 c, but the seedlings are liable to damp off. It is important to water them with care and to ensure that they get plenty of ventilation. Watering them with a garlic infusion can also help to prevent damping off. Prick out the seedlings into individual pots when they are about 25mm tall, and grow them in light shade in the greenhouse for at least their first winter. Plant them out in late spring or early summer. The seedlings are susceptible to spring frosts so might need some protection for their first few years outdoors. The leaves remain very small for the first few years. If you want to grow from cuttings, use half-ripe wood 3-6cm long, and in July/August place in a frame in a shady position. They form roots in late summer or spring. A good percentage usually take. Division can be carried out at almost any time of the year, but works best in the spring just before new growth begins. Very easy, larger clumps can be replanted directly into their permanent positions, though it is best to pot up smaller clumps and grow them in a cold frame until they are rooting well. Plant them out in the spring.”

I consulted the book, Seeds of Woody Plants in North America by James A. Young (Dioscorides Press, 1992, rev.ed.), and the general information on Gaultheria states that cold dry storage will help maintain seed viability. G. procumbens has 6800 seeds per gram. Seeds are initially dormant and prechilling is needed for germination (from 30-120 days with a variety of substrata). Salal (G. shallon) seeds appear to require light for germination. This resource says that G. procumbens seeds should be sown in the fall.

Gaultheria, Germination, Woody plant propagation

Rhododendron won’t bloom

This is the second year in a row that my rhododendron Blue Peter has flower buds but they are dry and somewhat dark and have no flowers at all. These buds are easy to deadhead. Can you help me salvage this rhododendron, which is very old, and beautiful when it blooms?

In order to get an accurate diagnosis you will need to take a sample of your plant (including both healthy and affected parts if possible) to a Master Gardener clinic. If they do not know what it is, ask them to send the sample to the pathology laboratory in Puyallup. It is best to go through Master Gardeners first so you will not be charged. If you send the sample yourself there will be a fee.

Meanwhile, several sources mention frost, drought, and “bud-blast” (unlikely in the Pacific Northwest) as potential causes of bud failure. Damaged flower buds and poor bud set: It is always most disappointing when fat, healthy looking flower buds either fail to open at all or only open a percentage of their buds, the rest being black and dead. Some rhododendrons regularly abort some or even all of their buds for no apparent reason. This may be due in some cases to a deficiency, perhaps magnesium, or to drought reports from various places give mixed results from applying magnesium (usually as Epsom salts)… By far the most usual cause of bud damage is frost. Flower buds are invariably less hardy than the rest of the plant so a really hard winter is sure to cause losses to flower buds. Early autumn frosts can damage buds that are not fully hardened off. This is a very annoying type of damage that may be overlooked and may not be noticed until the buds attempt to open in spring. Rhododendrons vary greatly in their ability to harden up enough to withstand early frost. In areas very prone to spring frosts, it is better to avoid growing plants that always burst into growth at the first sign of spring. Plants that frequently loose their first growth flush (and sometimes even their second) are liable to become stunted and rarely flower.

Source: The Cultivation of Rhododendrons, by P. Cox, 1993, p. 244.

Failure to flower, Frost, Master gardeners, Rhododendron

Growing conditions for Coleus forskohlii

I want to know about Coleus forskohlii a plant of South Africa. What growing conditions does it need, and what are its medicinal properties?

The plant you ask about is Coleus forskohlii (also known as Plectranthus forskohlii) in the family of plants called Lamiaceae. If your growing conditions resemble those of its native range (it grows wild in parts of West Bengal), you may be able to grow this plant.

The article entitled “Development of Coleus forskohlii as a medicinal crop” (no longer available online) from the Food and Agriculture Organization gives much information of interest. Here is an excerpt:

Coleus forskohlii grows wild on sun-exposed arid and semi-arid hill slopes of the Himalayas from Simla eastward to Sikkim and Bhutan, Deccan Plateau, Eastern Ghats, Eastern Plateau and rainshadow regions of the Western Ghats in India. Latitudinal and altitudinal range for the occurrence of the species is between 8 degrees and 31 degrees N and 600-800 m respectively. The species was studied for its ecological preferences in its native habitats throughout its distribution range excluding Eastern Plateau, Sikkim and Bhutan. Before the botanical studies were undertaken, the species was studied in the regional floras and herbarium specimens were examined in seven zonal herbaria of the botanical survey of India at Dehra Dun (Himalayan flora), Allahabad (Central India flora), Shillong (northeastern India flora), Jodhpur (Rajasthan flora), Pune (western India flora), Coimbatore (southern India flora) and Port Blair (Andaman and Nicobar group of islands flora), as well as at the Forest Research Institute, Dehra Dun and the Blatter Herbarium in Bombay. Eleven representative ecogeographic areas were selected for habitat and population studies; between 1982 and 1985, 27 botanical trips were made for the purpose. Coleus-growing areas in the Himalayas in Uttar Pradesh were visited every month from April to December, and the other areas were visited at least twice during the blooming period. The following is the summary of the observations made on different populations and habitats of C. forskohlii (Shah 1989).

C. forskohlii is a subtropical and warm temperate species naturally growing at 600-1800 m elevation

The species grows on sun-exposed hill slopes and plateaus in arid and semi-arid climatic zones

The species inhabits loamy or sandy-loam soil with 6.4 to 7.9 pH

The species is herbaceous with annual stems and perennial rootstock

The medicinal uses of this plant have not been evaluated fully for safety. Sloan-Kettering Cancer Center also has useful information about Coleus forskohlii. Here is a brief excerpt: “Very limited data are available concerning the efficacy of forskolin. Most studies performed with forskolin have been human trials; those performed on heart failure and glaucoma are inconclusive.”

As with any drug or herbal medicine, you should consult a medical professional if you have questions about its use.

Coleus, Medicinal plants, Plant care

Lunar gardening

I’ve heard that planting the garden according to phases of the moon has some benefits, but I’ve always wondered if there’s any truth to this. Is there any research out there on this topic?

Thank you for your interesting question. I found comments from the point of view of an astronomer on Cornell University’s “Curious About Astronomy?” webpage, excerpted here:

“There are two main ideas behind moon gardening practices. First, lunar gardeners believe the moon’s gravitational pull affects the flow of moisture in the soil. Just as the moon has a noticeable effect on the oceans in the tides, the moon may have a subtler effect on smaller bodies of water and thus change the levels of water in the soil. For example, to take advantage of the lunar cycle, a gardener would avoid turning over the soil in his or her garden when there is the most moisture in it (and thus when the soil was hardest to turn over) which lunar gardeners propose is during the new and full moons. Another, less direct, proposed connection between the moon and gardening is that moonlight is thought to have an effect on seed germination because exposure to light can enhance germination.

“I could not find any extensive scientific studies conducted to test the proposed benefits of lunar gardening. There was a study done by the Agricultural Research Service in Iowa where they found a link between weed germination and exposure to light. They determined that tilling the soil (i.e. bringing weeds to the surface) was best done at night by a new moon (when there was as little light as possible). Tilling in the dark led to less weed seed germination and thus to fewer weeds in the garden.

“More studies definitely need to be done to test the possible connections between the Moon and gardening before I am convinced. However, I would bet that with the extra care and attention lunar gardeners give their gardens, the gardens benefit whether the success is due to the Moon or not.”

For more information on the ideas behind lunar gardening check out Caren Catterall’s site, Gardening by the Moon.

Here is another interpretation, from an individual who tested to see if moon planting made any difference in the success of crops, from Undeceiving Ourselves:

“Gardening folklore in general is often based on accurate observation. It’s just that the reasoning may be faulty. For example, over the years I’ve tested various bits of ‘companion planting’ folklore. And some actually work, but not because ‘basil likes tomatoes’ (which actually doesn’t work because basil planted near tomatoes tends to get black spot, while the tomatoes do neither better nor worse). Never trust a gardening book that tells you that marigolds deter aphids–beans, onions and fuchsias planted with marigolds get more aphids, not fewer, and I suspect the same is true of other plants. On the other hand, root knot nematodes do appear to avoid the root secretions of marigolds, though a companion crop of marigolds can make the problem worse for other reasons. So remember that a gardening observation (like Moon planting) may be true even though the reasoning is faulty.”

There are journal articles which discuss lunar gardening. Here are a few:

Weird or wonderful? (organic farming) by Paul Kingsnorth in The Ecologist, February 2008. Abstract: Different kinds of gardening techniques have come up like planting according to the phases of the moon that promises higher yields and better flavors. There is also biodynamic growing that claims to be founded on a holistic and spiritual understanding of nature.
La lune et la nature vivante (The moon and living nature) by Lucien Baillaud in Revue des Sciences Naturelles d’Auvergne, 2003. Abstract: Popular traditions regard the effect of the moon on plants. Patented researchers strive to track
lunar influences without a known functional rule: many people of the sciences disagree with their results. These questions present themselves in very diverse manners to those who observe nature, to those who cultivate their gardens, or to those who try to reason.
Fractured Physics by Lynne Johnson in The Physics Teacher, Vol. 32, May 1994
Lunar Gardening: common sense or lunacy? by Kat Neely Jones in GreenPrints, Summer 2007
Lunar-Sidereal Rhythms in Crop Yield: A Review by Nicholas Kollerstrom and Gerhard Staudenmaier in Biological Agriculture and Horticulture, 2001, Vol. 19, pages 247-259. Online version.

The book The Old Farmer’s Almanac Book of Garden Wisdom by Cynthia Van Hazinga (Random House, 1996) also has a brief discussion of gardening by the phases of the moon, and mentions it as a principle of biodynamic gardening. The following information on biodynamic gardening comes from National Sustainable Agriculture Information Service’s resources (no longer available online), excerpted here:

“Planetary Influences

“Lunar and astrological cycles play a key role in the timing of biodynamic practices, such as the making of BD preparations and when to plant and cultivate. Recognition of celestial influences on plant growth are part of the biodynamic awareness that subtle energy forces affect biological systems. A selection of resources are listed below. On examination of the variations in agricultural calendars that have sprung from the biodynamic experience, it is apparent that differing viewpoints exist on which lunar, planetary, and stellar influences should be followed.

“Stella Natura – The Kimberton Hills Biodynamic Agricultural Calendar (…) is the biodynamic calendar edited by Sherry Wildfeur and the most prominently known calendar of this type in the United States. It contains informative articles interspersed with daily and monthly astrological details, and lists suggested times for planting root, leaf, flowering, and fruiting crops.

“Working with the Stars: A Bio-Dynamic Sowing and Planting Calendar (…) is the biodynamic calendar based on Maria Thun’s research and is more prominently used in Europe. Of the three calendars mentioned here, Thun’s calendar relies more heavily on planetary and stellar influences. It contains research briefs as well as daily and monthly astrological details, again with suggested planting times.

“Astronomical Gardening Guide, available through Agri-Synthesis in Napa, California for a self-addressed stamped envelope, is the biodynamic gardening guide compiled by Greg Willis of Agri-Synthesis. This calendar, which is a simple 2-sheet information leaflet, focuses on lunar phases.”

Lunar gardening, Planting time

Training goji berry vines

I am growing goji berry plants in my garden. I was hoping their growth habit would be more upright but they are sprawling wildly. Do you have suggestions for training them? Should I be concerned that they might become invasive?

Susanna Lyle’s book Fruit & Nuts (Timber Press, 2006) says these shrubby vines are short-lived, peaking in berry production at about 5 years of age and typically living for 8 years or so. She advises planting them near a fence or trellis so that they can be trained up it; some sprawling is to be expected. Utah State University Extension’s October 2015 article, “Goji in the Garden,” offers general cultural information (while mentioning that the plant is a weed in some areas).

Lycium barbarum (goji, also called wolfberry and boxthorn) can be invasive (or at least aggressive) in some areas. An article by Vern Nelson in The Oregonian (August 17, 2008) mentions this tendency, and suggests containing them in a 4 by 5-foot square support structure. Be aware that “wolfberries take root wherever they touch the ground.” This is worth bearing in mind, as is the fact that Lyle’s book says “the extensive root system can help stabilize banks,” which one could interpret to mean that removing unwanted plants might be a fair bit of work!

Suckering roots are only one way the plant spreads; seeds are another. Goji berry (boxthorn) is the “Plant of the Month” in the Whatcom County Master Gardeners Weeder’s Digest from August 2006. Author Cheryll Greenwood Kinsley notes that when the plant was first introduced in Europe, people weren’t enamored of the fruit but birds were, and now “the shrub has naturalized in Britain and is listed as a noxious weed on two continents and in at least some parts of several states, including Montana and Wyoming.” She recommends keeping the birds away from it to discourage its spread.

Invasive plants, Lycium barbarum, Training plants