I am a collector of Cyclamens and grow most of my collection in pots. I believe my C. purpurascens are infected with Botrytis, though I have not had this confirmed by any tests. Last year was particularly bad and I had to remove nearly every leaf from both my plants. This summer, as the new leaves emerged, I sprayed the leaves and surface of the grit with a sulfur solution, which seemed to dramatically reduce the infection rate. Now, the infection seems to be back. Can you suggest some methods of control? Do I have to have it confirmed first? I repotted them early this summer, and sterilized the pots and replaced the grit at that time. What else can I do?
What you have done to control Botrytis is what is recommended by the Pacific Northwest Plant Disease Management Handbook. It does indicate the Botrytis can be seed-borne and grow systemically in the plant. Your real solution may be to obtain plants that are certified disease free.
However in researching Botrytis online, I found an article, “Botrytis Blight of Flowering Potted Plants” in Plant Health Progress, from Plant Management Network International. This article was written by a researcher at Cornell University who suggested that Cyclamen are also susceptible to Fusarium wilt and that the symptoms are quite similar. Therefore, I do think it would be wise to take a sample of your diseased plants to a Master Gardener clinic for confirmation. The Master Gardener clinics in Thurston County can be found at their website.
I am new to the area, and am renting a house that has 3 containers of bamboo plants on the deck. Two of them appear to be dead or dying, although there is still green in the canes. I tried watering them a lot for a week or so, and for one day they seemed to like that, but then they did not any more, and looked worse. Some theories people have offered: the soil is depleted, they need to be thinned, they have been poisoned somehow. Any advice? Or should I just get new ones? And, where would I get new ones?
Bamboo can grow well in containers, but it can also be picky about drainage, fertilizer and container depth.
Here is an American Bamboo Society article (now archived) entitled Planting and Caring for Bamboo.
Your bamboo may have a pest or an infestation of some kind. To be sure, you may want to bag a sample of the leaves and take them to a Cooperative Extension Master Gardener Plant Clinic. Master Gardeners are trained in the identification of plants and pests and a host of other botanical subjects.
To find out where to purchase bamboo locally, try Bamboo Web’s sources search tool.
My rhododendrons have a problem. What appears to be a white powder covers the buds and spreads up the leaves. What is it, and what can I do to stop it?
I cannot be absolutely certain without seeing the plants, but it sounds as if your rhododendrons could have powdery mildew.
Here is an article from the Washington State University Cooperative Extension which describes this disease. One preventive measure you should certainly take is to clean up all the fallen leaves and twigs under your rhododendrons, because the fungus which causes powdery mildew can overwinter there.
You could bring in a sample to a Master Gardener Clinic, and ask if they can diagnose the disease as well (they are at the Center for Urban Horticulture and other locations–see their website.
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.
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.
The bark on a Coral Bark Maple is peeling away on one side of the trunk…about 1 1/2 to 2 feet long. The tree looks healthy otherwise. Cause? Anything to do?
Trees (maples and others) are attacked by various diseases and pests, but nothing that removes sections of bark on a trunk. Damage might be from larger pests such as raccoons, deer or squirrels. In the city, squirrels often strip bark from trees for their nests. You might want to:
1. Put chicken wire or other protective barrier around the tree. The tree will heal itself as long as the entire trunk is not girdled (that is when bark is stripped all the way around the trunk so moisture and nutrients can’t flow).
2. Have an arborist look at the tree for an accurate diagnosis. To locate an arborist in your area, contact Plant Amnesty’s referral service or call their Referral Service Coordinator at 206-783-9813 and leave the following information:
Name
General Location (city or town)
Phone Numbers (work, home, cell)
Email (will get the quickest response!)
I have a dark purple lilac tree growing on the north side of my home. It does not get a lot of sunlight. I am wondering about replanting it somewhere else in the yard. When can I do this?
Lilacs should be able to tolerate moderate shade, according to The Plant Care Manual by Stefan Buczacki (Crown Publishers, 1993). You can move it to a sunnier location to see if it will thrive there.
The best time to transplant a lilac is before it leafs out (late winter, when it is dormant) but apparently they are somewhat tolerant of being moved at less-than-ideal times. The University of British Columbia Botanical Garden discussion forum also recommends transplanting lilacs in dormancy. Blooming should not be affected, unless your bush is already leafed out and in bud.
I am trying to select plants for a green roof on Lopez Island. I would like to use some native plants, and not have to do too much weeding. Can you help me?
The Miller Library has a booklist on green roofs which includes weblinks. With respect to weeds, as a former professional gardener I don’t believe there is a “maintenance-free” garden. However you may be able to come up with a freely seeding grass (Festuca ovina var. glauca comes to mind) that would do well and look good with other plants.
Regarding Pacific Northwest native plants (i.e., grasses), I recommend using a native plant book (such as Pojar and MacKinnon’s Plants of the Pacific Northwest Coast) and searching for those which suit the conditions of the site. You may also find King County’s native plant
guide useful, as it is searchable by site requirements. Washington Native Plant Society offers a similar plant selection guide. There are also native species of Sedum.
The book Green Roof–a Case Study by Christian Werthmann (Princeton Architectural Press, 2007) evaluates green roof plants and planting techniques, and includes observations regarding soil depth, the factors affecting desiccation (i.e., metal edging and the planting medium/size of the plants used), and density considerations. Here are some of the conclusions of the case study:
- p.69-insects and other invertebrates need >6″ of soil to survive the cold;
drought tolerance increases with soil depth; probability of seed germination also increases with soil depth
- p.76-erosion control (bird repellant?) made from a degradable straw mat (such a mat may be useful for preventing birds from pulling up the plugs)
- Plants:
p.95-sweet fern Comptonia peregrine-not too vigorous, suffered from weed infestations
p.96-prickly pear Opuntia fragilis-did well
Phlox subulata, Silene caroliniana-did well
Sedum telephioides, S. lanceolatum, S. stenopetalum-suffered from heat, drought, and birds-these were replaced with European sedums (S. album, S. reflexum, S. spurium, S. cauticola, S. sexangulare, S. floriferum, Sempervivum tectorum, Orostachys boehmeri) and not planted as plugs but as larger plants that started in the green roof substrate (reducing transplant shock)
p.100-mixed prairie perennials with sedums (in 6″ soil), which filled in when perennials died-the architects note that there is no record of prairie plants doing well on green roofs, therefore the backup with succulents-they also note that metal roof edges speed up desiccationPerennials included ice plant (Delosperma nubigenum; my note: be careful about this, as it’s a noxious weed in California and if it spreads by seed, it might become a problem on Lopez); flameflower (Talinum calycinum); Eragrostis spectabilis; Allium schoenoprasum; Allium cernuum; Bouteloua gracilis; Elymus virginicus; Achillea millefolium; Tradescantia bracteata; Solidago nemoralis; Artemisia ludoviciana; Coreopsis verticillata; Asclepias tuberosa; Rudbeckia hirta
p.105-in 3″ soil with nearby metal (and thus an overheating issue), they used proven sedum species; heat from metal can be reduced by using aluminum (proved cooler than wood)
p. 108-conclusions: use a combination of indigenous plants with “successful green roof performers”-thin soil and high light “even overtaxed the hardiest succulents”-soil depth and temperature extremes made a big difference; even a slight difference in soil depth in a harsh environment can mean the difference between success and failure-continuous care and maintenance in the beginning is important for success-plugs grown in peat moss were less successful, since completely dried-out peat moss repels water-dense plantings (and/or rapidly spreading plants) important because bare soil gets hotter than soil covered by a plant.
I’ve never done any canning before but now that I’ve started growing more of my own fruit and vegetables I want to know how to do it safely! I’ve heard about a few different canning processes (water bath and pressure). Is one method or another best for certain types of food?
There is a very helpful article for canning beginners in the July/August 2012 issue of Urban Farm magazine, entitled “Oh, You Know I Can!” by Lindsay Evans. You mention the only two canning methods which the article says are approved by the U.S. Department of Agriculture as safe, water-bath and pressure canning. Their National Center for Home Food Preservation has extensive information. Here are excerpts:
Proper canning practices include:
- carefully selecting and washing fresh food,
- peeling some fresh foods,
- hot packing many foods,
- adding acids (lemon juice or vinegar) to some foods,
- using acceptable jars and self-sealing lids,
- processing jars in a boiling-water or pressure canner for the correct period of time.
Methods that are NOT recommended are open-kettle and steam canning, or using the oven or microwave to process filled jars.
The article has a handy list of which foods work best with water-bath canning, and which with pressure canning. Generally, high acid foods (pH level of 4.6 or less) can be processed with the water-bath method and low acid foods (pH of 4.6 or more) must be canned using pressure. High acid foods include apples, apricots and other stone fruit, berries, cherries, lemons, pears, tomatoes, pickles and sauerkraut. Low acid foods include asparagus, beets, carrots, corn, green beans, lima beans, rutabagas, and turnips.
Here is a link to more canning information from the National Center for Home Food Preservation.
I have a young 5-foot tall Hollywood juniper. How do I prune it to shape and train it so it looks good?
Because of the natural beauty of its form, Hollywood juniper, or Juniperus chinensis ‘Torulosa’, is not a good candidate for pruning, and I would recommend only pruning branches which are interfering in some way, such as intruding into a walkway. Below are links to information on pruning junipers:
University of Georgia Extension
Excerpt:
“Junipers do not tolerate heavy pruning because of the lack of new growth on old wood. This makes it important to know the growth habit of a particular juniper prior to planting so that future pruning can be minimized. Junipers can be tip pruned and thinned, but not cut back to large limbs. Pruning out old. dead foliage underneath creeping junipers will often contribute to better air circulation and thus better health of the plant.”
University of Florida Extension
Excerpt:
“Torulosa Juniper develops into a showcase specimen without pruning and is probably best used for this purpose.”
In her Guide to Pruning (Sasquatch Books, 2006), local pruning expert Cass Turnbull advises strongly against shearing and cutting into old wood, because you will be looking at woody stubs for a long time, if not forever. You can remove lower limbs which may be blocking sidewalks, but in general, avoid pruning. “Junipers, like most conifers, are difficult to prune. This is because the barren portions of the branches can’t produce new greenery (break bud) once the exterior green has been removed (headed back). Never expose those ugly, barren internal branches . . . What little can be done to help an overgrown planting involves removal of the lowest limbs, and/or selective heading (grab and snip) or thinning off the worst, most interfering branches. Always hide the cut beneath some natural-looking greenery.”
Your young plant should shape and train itself without the intervention of pruning.
Where can I find a list of foreign nursery catalogs?
We have many foreign nursery catalogs at the Miller Library, as well as a list of what we have. Call us at 206-543-0415 or 206-897-5268 (every day but Sunday) and we can fax you the list. Or stop by and look at the catalogs. Library hours and directions to get here can be found here.
In addition, the Royal Horticultural Society has a plant finder online. Go to this link and follow the instructions. You can either search by plant or by nursery (name, region, or specialty).
The commercial website Dave’s Garden has a section on mail-order gardening and nursery catalogs, including some foreign ones.