on “green” weddings and gifting tree saplings

We are planning to have a ‘green’ wedding, and thought about giving baby trees to our guests as favors, as a way of giving a gift that will leave an environmental legacy. Do you know of any sources?

I have had several questions like yours in the past, and I usually recommend substituting flower or vegetable seed packets, or perennials (including edible plants like herbs) for saplings. Many of the saplings available are conifers which mature into large trees–often too large for smaller home gardens, unless the residents intend to make them into bonsai specimens. Summer is probably the most labor-intensive time to plant a tree, because of the greater need for irrigation. That being said, there are numerous companies which market ‘baby trees’ (seedlings) as gifts. Here are just two examples:
Tree in a Box
Green World Project

If you want a green gift which is sustainable, I recommend giving low-maintenance perennial plants which have a high likelihood of survival even in a small home garden or apartment balcony. Another alternative is to donate an amount to an organization that reforests or restores natural areas, and then provide a certificate to each guest saying that a tree has been planted to mark the occasion of your wedding. See links to various organizations that take donations below:
American Forests
Arbor Day Foundation
The Heifer Project

controlling codling moth on apple trees

What can I do to control codling moth on my apple trees? I’ve tried the nylon footies, but found that the damage was actually greater. It seems as if the rough texture of the stockings actually makes it easier for the pests to get a purchase on the surface of the fruit. Also, the stockings give the fruit a slightly off (petroleum-like) flavor. I don’t want to use toxic chemicals.

The web site for City Fruit has useful information about codling moth, including life cycle, traps, and preventive cultural practices (good garden hygiene includes not leaving fallen fruit on the ground, and thinning your apples when they are small–marble or walnut-sized–to one per fruit cluster).

There are several control options described by University of California’s Integrated Pest Management page on codling moth.
Excerpt:
“Organically acceptable tools for the control of codling moth include cultural control in conjunction with mating disruption and sprays of approved oils, codling moth granulovirus (Cyd-X), the Entrust formulations of spinosad, and kaolin clay (Surround).”

A local home gardener told me that she has had good luck using Surround kaolin clay. You do have to apply it several times (from late June on, every week or two), and it will make your trees look a bit ghostly, but it is worth a try. This Washington State University HortSense page focuses on apple maggot control, but lists kaolin clay as a preventive method.
A thorough description of Surround kaolin clay spray may be found on the site of the National Sustainable Agricultural Information Service.

resources for tracking updates in plant taxonomy

Is there an online resource for tracking updates in plant taxonomy?

You may not be able to find up-to-the-minute, late-breaking changes, but you can search by plant family, genus, or species in the following online resources which are considered authoritative on plants and their scientific names:

1. You can download the USDA’s Complete Plant List. You can search for plants by scientific or common name here as well.

2. The GRIN database (also maintained by the USDA) offers several searching options and provides information on changes for each plant retrieved.

3. The International Plant Names Index also allows you to search for plants by scientific name; in addition, you can search for publications.

4. Here are two more name databases for plants in various parts of the world:
Multilingual Multiscript Plant Name Database and Flora Europaea.

5. Missouri Botanical Garden’s Tropicos website is another source of information on changes to plant names.

6. The Royal Botanic Gardens, Kew maintains The Plant List: A Working List of All Plant Species.

7. Here are two links to more information about taxonomy.

Kew Gardens has information about why plants change their names.

The (now archived) Horticultural Taxonomy Group (HORTAX) was set up in 1988, with the objective of providing a forum for taxonomists and horticulturists in the British Isles who have an interest in the taxonomy and nomenclature of cultivated plants.

8. There is a journal called Taxon, available online to subscribers, and available to Miller Library patrons using the library’s computers.

water-wise gardens in Washington state

Where in Washington State can I find examples of public gardens designed to be drought-tolerant xeriscapes?

There are Master Gardener Demonstration Gardens around the state, such as Riverfront Park Demonstration Garden and others in Wenatchee. There is also a WaterWise demonstration garden in Woodinville.

There is a water-wise garden in the Bellevue Botanic Garden.

There is a native plant garden maintained by the Tacoma Garden Club at Point Defiance Park.

Seattle Tilth maintains several demonstration gardens, including the Good Shepherd Center in the Wallingford neighborhood in Seattle and Bradner Gardens Park at 29th Ave. S. and S. Grand Street, in south Seattle. While not exclusively xeriscapes, their gardens employ water-saving techniques.

on pruning raspberries

It’s late September and my raspberries are done producing fruit. The canes are really tall. How should I go about pruning them?

According to Linda Gilkeson’s Backyard Bounty: The Complete Guide to Year-Round Gardening in the Pacific Northwest (New Society Press, 2018), the simple method is to wait until the dormant season and cut down canes that bore fruit last year. (You can tell these canes by their rougher and darker grey bark, compared to the lighter and smoother canes of the last growing season.)

This will work for summer-bearing as well as everbearing varieties, but some choose to prune everbearing (also called primocane-fruiting) raspberries in two stages. An everbearing raspberry is one that produces fruit in the early fall of the first year on their primocanes. It then fruits a second time, in June, on buds below those which fruited the previous fall. In the dormant season, prune off only the top part of the canes that have fruited, and let the remainder fruit next summer. Then you can prune out the whole spent cane the next winter. Try to keep only five to ten new canes per plant.

This Oregon State University Extension guide to Growing Raspberries in Your Home Garden may also be helpful to you.

pine species that produce edible nut in the PNW

Which pine species are the best for edible nuts? Are any of the pine trees that grow here in the Pacific Northwest possible sources? The cost of store-bought pine nuts is prohibitive, and it would be nice to be able to forage locally.

According to The New Oxford Book of Food Plants by J.G. Vaughan and C. Geissler (Oxford University, 1997), different species around the world have seed kernels which are used for edible purposes. In Spain, Portugal, and Italy, the main source is stone pine, Pinus pinea. In the southwestern United States, Pinus edulis (piñon pine) is used. In the western United States, the best source is Pinus monophylla, single-leaf piñon. Other species used include P. cembroides, P. cembra, P. gerardiana, P. sibirica, and P. pumila. But it is Pinus koraiensis (Korean pine) which is by far the most common variety exported worldwide. This has led to problems, and a recent New York Times article expresses concern that the pine nut industry is having a negative effect on the ecosystems of Korea and the far eastern reaches of Russia. If you can find local sources of edible pine nuts, you will be saving the bears and boars and chipmunks from famine!

Of the edible varieties mentioned above, local author Arthur Lee Jacobson (Trees of Seattle, 2006) lists Pinus edulis, Pinus cembra, and Pinus cembroides as rare in Seattle; mature specimens of stone pine (Pinus pinea) are also uncommon, but there are examples in the Washington Park Arboretum, Laurelhurst Playfield, and the Hiram Chittenden Locks. Korean pine is very rare in Seattle, with examples in the Arboretum, Woodland Park, and the Locks. (Bear in mind that harvesting plant material—including seed kernels–from the Washington Park Arboretum is not allowed.)

You might try growing a tree of your own, selecting one of the species known to thrive here. The tree would have to be 10-15 years old in order to produce usable seed kernels.

This permaculture website has information on growing pine trees for their edible kernels. You will need some patience and dexterity (it takes time for pine nuts to mature, and it takes skill to harvest them).

rust disease and rust-resistant varieties of currant

Our flowering currant has rust disease. It flowers beautifully but looks hideous for most of the summer and fall until its leaves drop. We’re debating whether to remove it, though we love the reddish blooms. Is it affecting other plants in neighboring gardens (for instance, our neighbor’s Heuchera which has rust)? Are there varieties of currant that are rust-resistant?

Your currant (Ribes sanguineum) is probably infected with white pine blister rust (Cronartium ribicola), which also affects some edible currants. As the name of the fungal infection suggests, this is a disease that passes back and forth between its hosts–currants (which aren’t killed by it) and white pine or Pinus strobus (which is seriously harmed by it). Don’t feel guilty about the neighbor’s Heuchera rust, which is caused by a different fungus specific to that plant, Puccinia heucherae. However, if there are white pines within 1,000 feet, the disease could kill them.

The link above mentions that Ribes sanguineum is very susceptible to the disease. Several varieties of edible red currant are rated as virtually immune (‘Viking’ and ‘Red Dutch’), but these are not the type of currant grown for their highly ornamental flowers. I could not find any information about resistant flowering currants, but if there are pines in your neighborhood which have the fungal infection, the rust may continue to be a concern for any future currants you plant.

cold hardy evergreen Magnolias for the PNW

We are looking into growing evergreen Magnolias as part of our nursery stock. Do you know what varieties will be the most cold hardy in the Pacific Northwest, and will be able to handle heavy snow the best?

You may have already come across this garden forum discussion on this very topic on GardenWeb.

Great Plant Picks suggests the variety ‘Edith Bogue:’

“The slow growth and controlled size of ‘Edith Bogue’ make it a good choice for courtyard and patio plantings, and its branches have strong resistance to breaking in wet winter snows.”

Their site also claims the variety ‘Victoria’ is resistant to damage from heavy snow.

This article from the Arnold Arboretum mentions Magnolia virginiana ‘Milton,’ also evergreen and supposedly resistant to breakage from snow loads because of its smaller leaves:

“The leaves are smaller in all dimensions than those of M. grandiflora, better suited to dealing with the snow loads that can be the death of the larger species, even for those cultivars that are otherwise quite hardy.”

I looked at several of our books on Magnolias, but snow load doesn’t appear to be a consideration for the authors–perhaps they’ve never walked around the Pacific Northwest after a snowstorm, and seen all the sorry-looking evergreen Magnolias bent and broken in the parking strip gardens! I suspect that even the snow-load damage-resistant varieties are susceptible to a degree. I’ve been observing the ones in my neighborhood. Those with a more upright, narrow structure seem to fare just a little bit better (gravity may make some of the snow fall off the foliage?) than the really wide-branching ones.

pinching plants to encourage growth

I’m starting snapdragons and bachelor’s buttons for the first time. The bachelor’s buttons are growing a main stalk and then budding. They’re 6-12″ high. I want more flowers. Can I pinch them back?

Can I pinch snapdragons? Those are only a couple inches high.

I checked The Gardener’s A-Z Guide to Growing Flowers from Seed to Bloom (Storey Publishing, 2004) by Eileen Powell for the answer to your question. Powell suggests that for snapdragon (Antirrhinum species) you “pinch back young plants after four to six leaves have appeared to encourage a bushy habit. Feed lightly twice before first flowers appear […] Deadhead often. If blooms become scarce, cut back plants generously, then feed and water generously.”

For bachelor’s buttons (Centaurea cyanus), the author only suggests deadheading frequently to prolong bloom. A Colorado State University Extension article from 2001 entitled “The Year of Centaurea” describes pinching back:
“Many bachelor’s-buttons branch naturally, but you can pinch the growing tips to encourage more branching, bushier growth, and more flowers. C. americana does need to be pinched, or you may end up with single-stalked plants. Pinching perennial cornflower will also give you more flowers, but it isn’t required. For slightly larger flowers, you can remove the buds from young plants, but part of the charm of cornflowers is their small, thistle like blooms.”

on the benefits of spiders in the garden

I’d like to help a friend start gardening organically. She is concerned about spiders in her garden, especially around her lawn. She would like to know of safe ways of getting rid of the spiders so her children will not be hurt by them.

Generally, spiders are not a problem with lawns, and are certainly not normally seen in large numbers at one time. They are considered beneficial in the garden, as they eat other insects. We do not often encounter dangerous spiders here in the Pacific Northwest. The following links may be useful in reassuring your friend.

Colorado State University Entomology
Excerpt:
“Spiders are beneficial inhabitants of any garden, ecosystem, or home because of their important contributions to biological control of pest insects. Spiders are considered to be the most important terrestrial predators, eating tons of pest insects or other small arthropods every year. Spiders are generalist predators that are willing to eat almost any insect they can catch. They are abundant and found in most habitats. They only need to be left alone!“
Burke Museum’s Spider Myths by Rod Crawford
Excerpt:
“Myth: Spiders in the home are a danger to children and pets.
Fact: House spiders prey on insects and other small creatures. They are not bloodsuckers, and have no reason to bite a human or any other animal too large for them to eat. In any interaction between spiders and larger creatures like humans, the spiders are almost always the ones to suffer. It is so rare for spiders to bite humans that in a 30-year career of handling tens of thousands of live spiders, I personally have been bitten twice. Both bites had only trivial effects.
A person who is not an arachnologist would not likely be bitten more than once or twice in a lifetime. (‘Mystery bites’ which people thoughtlessly blame on spiders, don’t count! There are no invisible spiders…).
Very, very few spider species have venom that can harm humans, dogs, or cats. In most parts of the world, no spiders with medically significant venom have much chance of being found in houses. In the few areas that are an exception to this rule, the harmless house spider species still greatly outnumber the more toxic ones. And spiders whose venom happens to be more toxic to us, are no more likely to bite us on that account; they are unaware of our existence.
Why, why do people waste their time worrying about spiders? It is not spiders that are dangerous to your children; the dangerous ones are other humans!”

For more general information on organic gardening and lawn care, see the following: