propagating lilies by stem bulblets

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!

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 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.

on adding sand and manure to clay soil

We would like to put in a new lawn around a home where there were mostly weeds. The soil is very a heavy silt because it is river bottom land. I have access to free sand; however, I’ve heard conflicting advice regarding adding sand to clay — some say yes, others no. I also have access to a large supply of free horse shavings/manure from a horse stable. Would those shavings be good to add to the soil to help lighten it and add nutrients? I don’t want to go to the expense of bringing in topsoil if I don’t have to. What are your suggestions?

Adding sand to clay soil is not recommended as a way of lightening the soil, as it “may create a concrete-like structure”, according to the booklet Ecologically Sound Lawn Care for the Pacific Northwest by David K.
McDonald. Linda Chalker-Scott addresses the reasons for this in depth in “The Myth of Soil Amendments Part II”.

Instead of adding sand, David McDonald recommends trying to till in compost. At least two inches of compost tilled into the upper six to eight inches of soil is recommended, but four inches tilled into the upper twelve inches is preferable . Try to avoid doing this when the soil is waterlogged, as it may damage the soil structure.

Composting the horse manure and shavings you have access to could be a feasible way to obtain the compost to till into the soil. The Guide to Composting Horse Manure by Jessica Paige of Whatcom County WSU Extension discusses how to compost and use horse manure. She recommends curing such compost at least a few weeks before application, and adds that one to three months is a good, typical composting time in summer or three to six months in winter.

Alternatively, according to David McDonald, if there are a few months of warm weather between autumn and seeding time, you could simply till the fall leaves and grass clippings into your soil. Depending on your planned schedule, this could be very easy. (You can find McDonald’s full booklet “Ecologically Sound Lawn Care for the
Pacific Northwest: Findings from the Scientific Literature and Recommendations from Turf Professionals” online as a very large PDF.)

Another option might be to consider some sort of groundcover if you discoverthat establishing a lawn is an excessively extensive project. Carex species or possibly Juncus phaeocephalus phaeocephalus are more naturally adapted to heavy soils in wet areas than lawn grasses and so may be less work in the end. Though they would not be appropriate for a heavy traffic area, they would be grasslike in structure. Sagina subulata might be more amenable to heavy traffic.

rhododendrons and autumn frosts

A friend in Illinois has sent a photo this spring of a very healthy looking rhododendron – leaf buds fully elongated and beginning to unfurl, while the green, blunt flower buds remain unopened. The flower buds don’t look brown, diseased, frozen or injured, but they remain tightly closed, foliage bud growth preceding blooming. He says he has 6 plants doing the same this month. Possible reason?

Though we can’t diagnose plant problems by phone/email, early autumn frosts can inhibit flowering and not all buds are equally affected.

“Autumn frosts: These can lead to damage…if they either occur in early autumn or immediately after a late season warm spell. Continental climates with extremes of heat and cold are more likely to suffer sudden temperature changes than those with maritime climates…A sudden temperature drop will catch a plant before it has had a chance to reach maximum hardiness and it may suffer accordingly, even if normally perfectly able to withstand such a temperature in mid-winter…Speed of ripening varies considerably…There is also a variation in the hardiness of flower buds compared to foliage and growth buds. Commonly, flower buds may be as much as 10 F. less hardy than foliage…”
(Source: The Cultivation of Rhododendrons, by P. Cox, 1993, p. 119-120)

controlling root weevils and whiteflies

I have a line of Ward’s ruby azaleas. The three weakest ones have a lot of tiny notches in the leaves. I seem to remember the notches from the root weevil as being larger than these. Are the tiny notches from something else?

I also noticed that some of my dahlias have splotched leaves and that when I disturb the leaves, white-looking insects fly off the leaves. These flies apparently have spread to tomatoes as well. Are these whitefly? Will they disappear after the winter or is there some control I should use to prevent them from taking over?

First you need to get an accurate diagnosis of your problems. If you are in King County, you can bring samples to a Master Gardener Clinic. For information about Clinic hours see their website (Plant Clinic Schedule).

Oregon State University offers this information about root weevils and Rhododendron (which includes Azaleas). It describes using beneficial nematodes as a control.

According to Washington State University Cooperative Extension’s publication, How to Identify Rhododendron and Azalea Problems (1984), root weevil damage to foliage is not usually a serious problem. You can check for weevils with a flashlight at night to confirm that they are the source of the notches you are seeing. There are some Neem oil-based products that may be helpful, but they must be used at the correct times of year. See WSU’s HortSense page.

As for the dahlias and tomatoes, it is important to determine exactly what the insects are before proceeding with treatment. If they are whiteflies, you can put yellow sticky traps around the plants to trap them. University of California, Davis’s Integrated Pest Management site has other recommended control methods, including reflective mulch. You may not want to use insecticidal soap:
“Insecticides have only a limited effect on whiteflies. Most kill only those whiteflies that come in direct contact with them. For particularly troublesome situations, try insecticidal soap or an insecticidal oil such as neem oil or narrow-range oil. Because these products only kill whitefly nymphs that are directly sprayed, plants must be thoroughly covered with the spray solution. Be sure to cover undersides of all infested leaves; usually these are the lowest leaves and the most difficult to reach. Use soaps when plants are not drought-stressed and when temperatures are under 80 degrees F to prevent possible damage to plants. Avoid using other pesticides to control whiteflies; not only do most of them kill natural enemies, whiteflies quickly build up resistance to them, and most are not very effective in garden situations.”

Douglas fir insect pests

I have some large second growth Douglas firs in my yard that were topped about 20 years ago. The last several years, almost all of them have developed pitch oozing down their sides from up high. What might be wrong with my trees, and what do you think I should do now?

Disease and pest diagnosis is impossible without actually examining the affected plant. However, based on the symptom of oozing pitch you described, these Pseudotsuga menziesii (Douglas fir) could be suffering from one (or more) of the following pests:

Fir Beetle

Pitch Moth

Twig Weevil

For a proper diagnosis you could hire an arborist. The Pacific Northwest Chapter of the International Society for Arboriculture has a directory of certified arborists.

You could also take many photos and a plant sample to a Master Gardener clinic. This is a free service run by volunteers trained by WSU faculty. Clinic locations and times can be found at this website (Plant Clinic Schedule).

plant nurseries directory

Is there a print or online resource for locating plants (places where they are sold)?

You can search the Andersen Horticultural Library’s Plant Information Online. But be aware that they only include a selection of nurseries (those who post their inventory online). Most local nurseries are not included, as their inventory changes too frequently. There is another website, Plant Lust, which simultaneously searches 80 different nursery catalogs (especially Oregon-based nurseries). You can also search using your favorite search engine for the name of the plant you are seeking plus the word nursery. This will not give you any clues, however, as to the reputation of the nurseries which show up in your search results. The website of Dave’s Garden does have a forum of nursery reviews (called Garden Watchdog) you can consult.

managing aphids

I have just taken over management of the small landscaped yard for my condominium and we have two trees (weeping birches I’ve been told) in the front that appear to have been infested with aphids. The trees are about 15 feet tall and are located between the building and the sidewalk to the entrance. They have southern exposure. There’s a few evergreen bushes around the trees, no grass.

I am not familiar with aphid controls, so have done some internet research, including your very useful
site. We want to avoid using pesticides, so from what I’ve read, the best control is insecticidal soap.
Before I try to spray this on the trees I have a few questions I was hoping you could answer.

1. Can you verify that this is aphid damage?
2. It seems to me that the amount of white material on the undersides of the leaves has decreased in the last month. Given that it is getting late in the growing season, is it still worth treating the trees?
3. Does insecticidal soap seem like a good treatment in this situation, and if so do you have any application tips to make sure the undersides of the leaves are treated?
4. Do you have any recommendations for preventative actions to decrease the impact of aphids on these trees in the future?

Birches are commonly afflicted with aphids, and the aphids suck sap and secrete honeydew, which can be a nuisance, and is usually why homeowners contact us. Unfortunately, if your birches are overhanging a sidewalk, it is probably getting sticky from the honeydew. Otherwise, you could probably ignore the problem (except in the most severe infestations).

You can try spraying the aphids off the leaves with a strong jet of water. You can also encourage natural predators. Avoid over-fertilizing, or exposing the trees to lawn fertilizer, for example, as this will lead to succulent new growth which attracts aphids. Make sure the trees are not under any stress, as aphids are more likely to feed on a weakened
tree. You may be able to avoid using the insecticidal soap as a control. If you do use it, you are correct that you need to reach all leaf surfaces, which is labor-intensive. Some of these soaps can cause damage, so it is always a good idea to test any such spray on a small area before coating the whole plant. An article by Colorado State University Extension provides information on insecticidal soaps. Aphids go through many generations in a year, and their eggs can overwinter.

Toxic-Free Future (formerly known as Washington Toxics Coalition) has created a document on managing aphids in the landscape.

Here are additional links on aphid control:

Aphids from University of California at Davis

Managing Aphid Problems without Pesticides from the Northwest Coalition for Alternatives to Pesticides

tree peonies care and watering

I purchased a bare root tree peony at the NW Garden Show this year and it was doing just fine, getting to be about 1.5 feet tall until about two weeks ago and the entire plant is now drooping, the leaves quickly sagging. It is in a semi-shady spot that receives morning sun. I water all of my plants once a day unless it has been raining. I am trying to figure out if it is dying, and what I might do.

My first thought is that your tree peony is either responding to drought, or too much water. My own tree peony which is about 12 years old has always been sensitive to excessive heat and drought. It is in a partly shady location, but it has root competition from two nearby conifers. Watering less frequently but more deeply is usually a good idea. A commercial nursery site has the following information about this plant’s water needs. Excerpt:

“Watering: This is the most common misunderstanding. Tree peonies do not have watering needs like roses or other perennials. They are woody shrubs native to northern China, which receives about 30 inches of rain per
year. Once established, tree peonies are drought tolerant plants. Excess water will suffocate the roots and is the leading cause of plant failure. Do not plant near auto-sprinkler systems that keep the soils continuously moist. Do not water until soil is dry below the surface and try not to wet leaves when watering to prevent fungus. Be observant; soil can dry out on top and still be moist 6-12″ below the surface. When you feel the soil is dry below the first 4-6″ and leaves may droop slightly, water the roots deeply. Climates of hot summer temperatures with little or no rain at all will require more attention to watering then those areas that get some rainfall. Peonies in root control bags will require more watering attention than tree peonies planted in the ground. NOTE: Droopy leaves in the first warm days of spring are caused by an imbalance of the root system and leaf production. If soil has moisture, do not water. This imbalance that will self correct as the plant settles into the growing season. You know this is the cause of the limp leaves if the plant recovers in the evening or early the next morning.”

The other possibility is a fungal disease called peony wilt. Here is more information about this problem, from the Royal Horticultural Society. Excerpt:

“Tree peonies can be vulnerable to attack by peony wilt (Botrytis paeoniae), especially during wet springs. Symptoms are wilting of the flower buds, sometimes accompanied by a fluffy grey mould and, later in the season, brown blotches on the leaves. Botrytis forms sclerotia (hardened fungal bodies) in diseased tissue, which carry the fungus over the winter, so it is important to prune out and destroy infected tissues to prevent this happening. Currently no fungicides labelled for control are available.”

If you think that the problem may be wilt, and would like confirmation, you can bring samples of the leaves to a Master Gardener Clinic for diagnosis.

on controlling Japanese Anemones

Do you have any suggestions for controlling the spread of some too happy Japanese Anemones? I know they spread by underground roots but do they also spread via seeds? If I put down a barrier how deep should it go?

I have also experienced this in my garden, and it is not impossible to dig up Japanese anemones and either compost them or offer them to fellow gardeners (with a stern warning!). Anemone x hybrida spreads easily by roots but can be propagated from seed. It is most likely that the spreading of the plant in your garden is mainly rhizomatous (by roots). If you don’t want to dig up the occasional clump, you could try getting rid of the plant in areas where you do not want it, and then putting barriers such as plastic edging around the clumps you want to keep, although I think this requires at least as much labor as removing any unwanted anemones. Also, cut off spent flower stalks if you want to avoid seeds. However, the seedheads are flossy and ornamental in winter.

Here is general information on this plant, from Cornell University.

Here is information from Iowa State University Extension(now archived). This may give you some ideas on ways of containing the spread of the roots.

Cedrus deodara dripping problem

My deodar cedar drips a lot and an arborist told me the tree has ongoing pest problems. Could the tree have aphids?

There are several possible causes for the dripping of your Cedrus deodara. It might be honeydew (from an insect infestation). There is a type of aphid, Cinara curvipes, the bowlegged fir aphid, which feeds on cedar bark. Large colonies of aphids can develop on the twigs or branches of host trees in the winter along the Pacific Coast, or in the spring inland. Vast amounts of honeydew can rain down if the infestation is heavy. If you shake an infested branch, aphids should drop from it.
(Source: Insects that Feed on Trees and Shrubs by Warren T. Johnson and Howard H. Lyon, 1994)

If, in addition to the oozing sap, the foliage is also discoloring and wilting, it could be caused by a root or crown rot.
(Source: Pests of Landscape Trees and Shrubs, 2nd edition, by Steve Dreistadt, 2004)

Since there could be many causes, it might make sense for you to bring in a sample to a Master Gardener Clinic. You can locate a Master Gardener Clinic within King County on this website (Plant Clinic Schedule, or statewide here.