gardening magazines specific for the PNW

Are there any gardening magazines with practical information that is specific to the Pacific Northwest?

There are numerous newsletters and small magazines from Northwest organizations like Seattle Tilth, Plant Amnesty, and Washington Park Arboretum. There are relatively few mainstream magazines that only discuss PNW gardening issues. Here are two which are published in British Columbia that you might try:

GardenWise (B.C.)
Gardens West (B.C.)

Feel free to come into the Miller Library and browse our periodicals collection, which includes the newsletters and magazines listed above.

The Miller Library website has many links to online resources, many of which are Pacific Northwest-specific. For example, you can find local organizations and plant societies, as well as websites specific to gardening in our region. Look at the Resources page on our website for booklists and recommended links.

differentiating critter mounds

I live in Seattle and have, for the first time this fall, noticed dirt mounds on my property. These mounds tend to be located near patios/driveways, and are not in the sod. They are loamy, with no apparent holes, and are about three to five inches high. I wouldn’t call them conical. There are no mole tunnels, and, as far as I can see, no bugs. The mounds are bigger than the little fine-grain mounds I have noticed in years past with small black ants crawling in them. Is there someone I can ask about what is causing these mounds, and if it is something to be concerned about? Could it be ants or mice?

From your description of the dirt mounds, it sounds as though the critter in your yard may be either a mole or a gopher. The easiest way to tell the difference is by the type of mound you have. Here is information on moles and pocket gophers from Washington Department of Fish and Wildlife’s Living with Wildlife website.

Below is additional information from “Of Bugs and Blights” (in Balls and Burlaps, February 1988, pp. 4 and 14):

A gopher mound fans out from a hole near one edge of the mound. This hole remains plugged while the gopher is on the runway system. The gopher mound is relatively flat compared to the mole mound. Gopher mounds vary from 1 to 3 feet in diameter…several mounds often will be found together. They are not regularly found in a line as are mole mounds. The mole mound is somewhat conical and not much over a foot in diameter. The hole is not evident when you look at the mound. Push the soil aside and you will find it under the center of the mound. Each mound is connected with the other in a line by the moles’ runway system.

According to the article quoted above, moles are more likely to be found in gardens in Western Washington than are gophers. We have the journal Balls and Burlaps in the Miller Library. The article discusses the problems and benefits of moles, as well as control methods.

I also consulted the Western Garden Problem Solver (Sunset Books, 1998) to see if I could identify your mound-maker. Ground squirrels leave their burrows open, so if your mounds show no opening, you probably don’t have squirrels. Mole mounds appear volcano-like, with signs of soil excavation.

Here is a link to information on ants and their nests which you might look at to see if the images resemble the mounds of soil you are seeing.

resources on container gardening

I am going to create container plantings for some customers, and I wonder if you know the best source (book) for combining plants in containers. Also, where might I take a class in container planting?

The Miller Library has a large number of books in its online catalog on container planting, but here are a few which may be helpful to you:

Container Gardens by Number by Bob Purnell (Reader\’s Digest, 2004)

Contain Yourself by Kerstin Ouellet (Ball Publishing, 2003)

The Complete Book of Container Gardening edited by Alan Toogood (Quarto Publishing, 1991)

The Book of Container Gardening by Malcolm Hillier (Simon & Schuster, 1991)

A Practical Step-by-Step Guide to Complete Container Gardening compiled by Ideas into Print (Whitecap Books, 1997)

This booklist will give you an idea of the selection of books on the topic.

UW Botanic Gardens occasionally offers classes on container planting,
as does Seattle Tilth.

Also, some local nurseries occasionally offer classes. One example is Swanson’s Nursery.

list of patented plants

Is there a published list of patented plants?

I was not able to find an accessible list of patented plants from the U.S. Patent and Trademark Office, but their website does provide information about plant patents. They also have a bookstore which sells printed “Index of Patents” issued in a particular year. Individual plant breeders may list their patented and patent-pending plants, as this example from PlantHaven shows. The plant breeders Proven Winners also have several informative pages about plant patents.

common diseases of plums

I have a flowering purple plum tree. For the last two years it has had
black knobby growths on the limbs. The number of these growths are
increasing and there is no sign of any type of bug involved. The tree
is healthy in all other respects and the growths remain on the limbs
all year. I cannot find anyone who knows what these are and if I need
to do anything to stop and/or remove these growths. Obviously they are
ugly but probably not fatal and do not spread to any other trees. Can
you give me a clue?

We can only guess from your description, and in order to get an accurate diagnosis you will need to take a sample (including both healthy and affected parts if possible) to a Master Gardener clinic. Click on the appropriate link for your local clinic through Master Gardeners / Washington State University Extension.

Meanwhile, for information about common diseases of plums in the Pacific Northwest, try searching Washington State University’s HortSense website.

The symptoms you describe are similar to 1. Crown gall, 2. Black canker and 3. Black knot. Click on those diseases for descriptions, photos, and control methods.

You can also take a look at pages like this one, on black knot of ornamental cherry and plum, from Morton Arboretum. See if the images resemble what you are seeing on your tree.

controlling white fly infestations

I have a white fly infestation on Helleborus. Is there any natural control (Rodale recommends tobacco tea) — anything less labor intensive?

According to The Organic Gardener’s Handbook of Natural Insect and Disease Control, edited by Barbara Ellis (Rodale Press, 1996), whitefly can be controlled in the following ways:

– Catch adults on yellow sticky traps.
– Vacuum adults from leaves.
– Attract parasitic wasps and predatory beetles.
– Spray with insecticidal soap, kinoprene (Enstar) or garlic oil.
– Last resort: spray with pyrethrin.

Meyer lemon plant dropping its tiny lemons

I purchased a small Meyer lemon plant from a nursery in Florence, OR, and it grew, and blossomed very well, and even produced many tiny lemons – all of which have now, at this point, dropped off. The leaves are yellowing, too. It is in a good size container, in full sun. The container sits in a large saucer which does fill with rainwater. This I empty, but the plant remains wet. New blooms are coming on some of the branches, old blooms are shrivelling. No more lemons coming as yet.

My question is, why did the tiny lemons drop off? And, should the plant get overly wet? My nursery person has no information. I would appreciate any information you have.

The following information comes from Citrus (by Lance Walheim, Ironwood Press, 1996).

It sounds as if your container has good drainage, but maybe the plant is getting too much rainwater. That might be causing the leaves to turn yellow. Another cause could be a nitrogen deficiency, which would be most visible in older leaves, which would yellow from the tip to the base.

As far as the plant’s water needs, it will need water when the top two to three inches of soil become dry. Frequent watering (or excess rainwater) can leach nutrients from the soil, so the plant will need to be fertilized regularly — once or twice a month using a liquid, high-nitrogen fertilizer that includes the micronutrients zinc, iron, and manganese.

The small lemons which drop off may not be anything to worry about, as fruit drop occurs normally as the tree varies its fruit load with its carrying capacity. Pea-sized fruit usually drop about one month after bloom. A more noticeable drop occurs in late spring to early summer, when golfball-sized fruit may drop. Other reasons for fruit drop could be conditions which limit tree growth, such as excess heat, lack of soil moisture (not relevant in your case), and fluctuating weather conditions. It is also possible that the fruit drop is due to lack of nitrogen.

Osmanthus fragrans hardiness in the PNW

Is Osmanthus fragrans hardy enough to withstand winter in Bellevue, WA?

Osmanthus fragrans is a borderline hardy shrub in our area. References vary in the hardiness they quote from zone 7 to zone 9 (Bellevue is zone 8). According to a gardener here at the Center for Urban Horticulture, “it takes a special spot for it to grow and thrive here in the Puget Sound area. The places where I’ve seen decent specimens and blooms are plants growing up against a warm wall or enclosed somehow by other plantings, buildings, or areas near pavement.” If you have a very sheltered spot, for example a courtyard where you could grow it against a south-facing wall, it might be worth a try. Otherwise it seems to be very risky.

deer-resistant Japanese Maples

Is the Japanese ‘Crimson Queen’ laceleaf maple deer resistant?

I found Japanese maple (Acer palmatum) on a few lists of deer resistant plants. (One source is Pacific Horticulture, v. 47 (3) 1986, “Co-Existing with Deer,” by Mary Lynn Cox)

None of the lists mention specific cultivars, such as your ‘Crimson Queen.’ But the risk of damage should be lower than other plants that deer prefer. Every article I read warned that a starving deer will eat anything, so no plant is 100% safe.

when you can’t plant right away

For how long can purchased plants remain out of the ground?

If the plants are in pots, they can stay out of the ground as long as needed. Keep them watered and they will be fine. But if they are bare root, then you should plant them temporarily (called heeling in) in a trench until you can get them into their proper holes. The most important thing to remember is to keep the roots moist. Keeping the plants out of the sun can help reduce stress as well. If digging a trench is impractical, then cover the roots with damp towels or burlap bags. Of course, planting sooner is better!