trees for waterlogged soils

Can you recommend some tree species (deciduous) that can have wet feet but
will also tolerate dry conditions in the summer? The recommendations should
be trees that are not too messy (no cottonwoods or alders, please) and not
too big. I would like to plant some trees near a swale in my yard – so they
could be sitting in soggy ground during the winter.

Following is a list of possibilities, most of which come from Water Conserving Plants
for the Pacific Northwest West of the Cascades (by the N.W. Perennial
Alliance, 1993). The list includes only trees that 1) thrive in soils
which are waterlogged in the winter, and, 2) grow to less than 40 feet tall.

ACER (maple):
A. buergeranum (trident maple)
A. campestre (field maple)
A. ginnala (Amur maple)
A. circinatum (vine maple)
CORNUS nuttallii (western dogwood)
C. douglasii (black hawthorn)
C. monogyna
C. phaenopyrum (Washington thorn)
C. x lavallei (Carriere hawthorn)
HOVENIA dulcis (Japanese raisin tree)
MALUS fusca (Pacific crab apple)
NYSSA sylvatica (black gum)
OXYDENDRUM arboreum (sourwood)
PRUNUS (prune/plum/cherry):
P. virginiana var. melanocarpa (chokecherry)
P. emarginata (bitter cherry)
PYRUS (pear):
P. communis (common pear)
P. pyrifolia (Chinese pear, sand pear)
QUERCUS (oak):
Q. acutissima (sawtooth oak)
Q. imbricaria (shingle oak)
RHAMNUS purshiana (cascara)

Plants poisonous to pets

Is a holly tree toxic to animals (dogs/cats)?

The ASPCA website on plants which are toxic to animals lists holly (Ilex spp.), as does the Humane Society website.

According to Plant Alert, A Garden Guide for Parents (by Catherine Collins; 2001), and Plants That Poison (by Ervin M. Schmutz and Lucretia Breazeale Hamilton; 1979)
the red or black berries on holly are poisonous to humans as well, and can be fatal to small children if eaten in quantity.

If you believe your dog or cat has consumed holly berries, call your veterinarian for advice as soon as possible, or call the ASPCA Animal Poison Control number, 888-426-4435 (not a free service).

on fertilizing geraniums

What would be the best fertilizer for hardy geraniums and when to fertilize?

Established hardy geraniums do not need much more than an application of compost in spring. Most commercial fertilizers will provide too much nitrogen, causing weak growth that flops over or needs staking.
(Source: The Gardener’s Guide to Growing Hardy Geraniums, by Trevor Bath, 1994)

walnut leaves in compost

Will black walnut leaves cause compost to be allelopathic? Should they be kept out of compost? Or is this folklore? The specific compost is made with chicken manure (fresh), grass clippings and walnut leaves. Are there plants that tolerate the toxin in black walnut?

It seems that the main source of toxicity is the roots of the walnut
tree, rather than the leaves or shells. However, there are still those
who believe that there is enough juglone in the leaves that they should
be fully composted before use in the garden. Below are excerpts from information published online in various university extension websites, by various authors, and now unavailable:

“This toxic affect on surrounding plants appears to be related to root
contact, as walnut hulls and leaves used as mulch have not shown toxic
effects on plant growth. [Warning- Frank Robinson disagrees.] Because Walnut
roots do not occupy the surface layers in most soil, many shallow rooted
plants growing under walnut trees don’t come in contact with the roots
and are not affected by them.” [Michigan State University]

“You’ve probably always heard that you should never add black walnut
sawdust [or wood chips] to the compost pile because the juglone will kill
everything that grows in the compost. Abraham says that’s not
necessarily true; that juglone is not found in walnut saw dust or wood
chips. Nor do dead walnut trees exude juglone. Juglone is harmless to
humans so you can go right ahead and safely eat fruit and vegetables
grown near walnuts.”[Katy Abraham]

“Robinson doesn’t agree on the use of walnut residue in composting. He
has this to say about black walnut saw dust, husks and leaves affecting
plants. ‘Tomatoes growing in clean soil in pots were severely stunted
when leaves and nuts fell into the pots while we were on vacation. I know
what juglone can do. I have seen a 15-year-old rhododendron killed a few
weeks after its owner mulched it with black-walnut husks, and roses
injured by an application of compost containing black-walnut sawdust.'”
[Robinson]

“The juglone toxin occurs in the leaves, bark, and wood of the walnut but
these contain lower concentrations than the roots. Juglone is poorly
soluble in water and does not move very far in the soil. Walnut leaves
can be composted because the toxin breaks down when exposed to air, water
and bacteria. The toxic effect can be degraded in two to four weeks. In
soil, breakdown may take up to two months. Black walnut leaves may be
composted separately, and the finished compost tested for toxicity by
planting tomato seedlings in it. Sawdust mulch, fresh sawdust or chips
from street trees prunings are not suggested for plants sensitive to
juglone, such as blueberry. However, composting of bark for a minimum of
six months provides a safe mulch even for plants sensitive to juglone.”
[Ohio State University]

“To be on the safe side, composted material containing juglone should be
allowed to breakdown over a period of time before use. This composted
material can be used with plants that are not susceptible to juglone
damage. If it is important to use it for general composting purposes,
testing it first with a few tomato plants for a few weeks should reveal
its level of toxicity.” [Abraham]

This may also be of interest: The Walnut Tree: Allelopathic Effects and Tolerant Plants from the Virginia Cooperative Extension.

Frank Robinson’s article “Under the Black Walnut Tree,” Horticulture magazine, October 1986, pp. 30-33 concludes that many plants are indeed able to tolerate juglone’s toxicity. Some of the juglone-tolerant plants listed in the article and in other sources are included on Morton Arboretum website.

growing roses in the Pacific Northwest

I would like more information on Rosa chinensis ‘Mutabilis’,
particularly regarding how it performs in a Seattle garden. I am most
concerned about black spot and any other diseases.

I am currently growing this rose for the first time, and it is blooming
profusely. I have needed to keep on top of the aphids (hand-squishing),
and there are a few yellowed leaves which drop (and which I have been
picking up and destroying as soon as I see them). Here is what the book
Roses for the Pacific Northwest by Christine Allen (Steller Press, 1999)
has to say about this rose:

Few old roses flower so continuously–cold weather merely turns the buds
a paler hue and, although they don’t then open, they remain fresh-looking
on the bush for weeks. It hates cold wind, but will take a surprising
amount of shade, forming an open, leafy shrub with soft red stems and
red-tinged foliage, impervious to disease.

I would not go as far as to say it is impervious to disease,
but my impression is that it is relatively disease-resistant. I am truly
enjoying the look and fragrance of this rose in my garden. Links to additional information:

An article by Valerie Easton in the Seattle Times

honeysuckle and common diseases

I noticed my honeysuckle, which is intertwined
to look like a topiary bush with the greens and flower all bunched
up at the top, to have yellowing of the leaves and drop off. Why
are the leaves yellowing? It smells lovely and is green on the
outside, but if you look under the canopy you can see many yellow
leaves. Is it a disease? Should I use a fungicide?

There are a few possibilities. It might be a kind of leaf blight, as
described by Iowa State University Extension.

Leaf blight is a fungal problem, but the control methods described above are not
nontoxic, so you may want to look for a safer fungicide (example here), and also
try to prevent the ideal conditions for fungus. Avoid wetting the leaves
of the plant, and make sure there is good air circulation around the
plant (by siting it properly, and by pruning to keep the plant’s shape
open).

Yellowed leaves could also be caused by scale, which is an insect. Do you
see small bumps on the leaves and stems? If so, here are recommendations
from The Organic Gardener’s Handbook of Natural Insect and Disease
Control edited by Barbara Ellis (Rodale, 1996):

“Minor infestations can be controlled by scraping the insects off the
plant with your fingernail, and by pruning out the most infested parts of
the plant. You can also use a soft brush and soapy water to scrub scales
off the stems, or you can apply dormant oil to the trunk and stems of the
plant just before growth begins next spring, and use superior oil during
the growing season.”

Because I’m not certain which type of problem your honeysuckle may have,
you should bring a sample to a Master Gardener Clinic.

weed-and-feed products and edible gardens

How soon I can plant my edibles after I’ve used weed and
feed?

Do you know which weed and feed product was used? That would help in
determining the chemical’s half life (persistence) in the soil. Regardless of which chemical was used, my
recommendation would be not to plant any edibles in a site which has been
treated with weed and feed, but to find another location for your food
plants (such as containers made of safe materials, or raised beds with a
barrier between the bed and the chemically treated area of the garden).

Local garden writer Ann Lovejoy has discussed weed-and-feed products in
her column. Here is a link.

Here is what retired Washington State University Extension agent Mary
Robson had to say on this subject in one of her columns no longer available online:

Just one note of caution-be careful with all chemicals. Many pesticides
ordinarily used in gardens are not allowed on edibles. An example is Lawn
Weed and Feed which will harm any broadleaf plant whether lettuce or
marigold or petunia. It’s probably safest to keep pesticides out of the
garden if you plan to eat the produce.

Formerly available from the website of Washington Toxics Coalition:

The Hazards of Weed and Feed

“Weed and feed is a mixture of lawn fertilizer with weed killer, usually
2,4-D and related compounds. The problem with weed and feed is that it is
designed to be applied to the entire lawn regardless of whether or not
weeds are actually present. This encourages over use. For example, if 30%
of your lawn is covered in weeds, 70% of a weed and feed application will
be wasted, since the herbicides have no residual action. Since many
people do not realize that weed and feed is a pesticide, they may be less
inclined to read an follow label instructions. For example, did you know
that it is illegal to apply weed and feed more than twice per year on the
same site?

“The herbicides in most weed and feed products are mobile in soils and are
widely found as pollutants in local streams, according to the U.S.
Geological Survey. In addition, 2,4-D is neurotoxic and may be a
carcinogen according to some studies.

“Weed control should be practiced only as needed, not every time you
fertilize. Mechanical controls are preferable to protect health and the
environment. If chemical controls are used, spot treatment should be
utilized to minimize product use and resultant risks from direct exposure
and track-in to the home on shoes and feet.”

Here are links to information on some common weed-and-feed type products
and their hazards:

From the Pesticide Action Network North America

From the Winter 2005 (updated April 2006) article in Journal of Pesticide Reform

on frisée lettuce

Is it safe to boil or steam French frisée lettuce (as one would with spinach and chard)? Does cooking the lettuce this way make it poisonous or inedible?

Frisée lettuce (Cichorium endivia) is not actually a lettuce, as this link from Yuma County (Arizona) Cooperative Extension says, but a leafy green related to endive and chicory. It is sometimes called curly endive, French endive, or escarole. There are at least 18 varieties. Leaves are eaten raw in salads, boiled, steamed, sauteed, braised, or cooked in soups and stews.The mature plants are sometimes blanched before harvesting to reduce the bitter flavor. In Java, they are pickled in brine.

Source: Cornucopia II; A Source Book of Edible Plants, by S. Facciola, 1998, p. 190, 362-363.

Frisée (confusingly called French endive by some) is almost a miniature version of curly endive or perhaps is more like the inner portion or heart of that plant. The outer leaves of frisée are light green to yellow, and the yellowing continues inside and becomes white at the center with a lace-like pattern with a milder taste than that of curly endive.

Frisee: A great little lettuce that is part of the chicory family. It is lacy and pleasantly bitter. As the lettuce grows, each head is tied up so that the sun does not penetrate the center of the lettuce as it finishes growing. This process blanches the frisee since the plant needs the sun to develop its normal green leaves. The delicate white leaves are considered a delicacy and are the least bitter.

Source:

https://www.specialtyproduce.com/produce/Frisee_512.php

plants at the Washington Park Arboretum

I’m thinking of planting the following plants in my garden but would like to see them first. Can you tell me if they are at the Washington
Park Arboretum? The plants are: Chinese Witchhazel, Witch Alder, Mountain Laurel, Soft Shield Fern, and Variegated Kiwi Vine.

The Washington Park Arboretum has many examples of Hamamelis mollis, or
Chinese witch hazel (unless you meant Corylopsis sinensis or Loropetalum
chinense, which also go by the common name ‘Chinese witch hazel’). Kalmia
latifolia (Mountain laurel) and Fothergilla (but not Fothergilla
gardenii, which is Witch alder) are also in the Arboretum. The variegated
kiwi, Actinidia kolomikta, used to be grown here at the Center for Urban
Horticulture. Soft shield fern, or Polystichum setiferum, may be in the
Arboretum, but is not listed, as it is not a woody plant. You can search the Washington Park Arboretum’s Living Collections database by the plants’ scientific or common names (sometimes it’s best to search the scientific name, for clarity). You can search the Arboretum’s interactive map and there is also a trail map linked here which provides information on large collections of plants, so you can get a sense of where to find things. You can go to the Graham Visitors Center in the Arboretum and ask for assistance in locating the witch hazels (some are in the Witt Winter Garden, and
others are in a grove on the south end of the park) and other plants.

All of these plants grow well in our area. I have a dwarf form of
Fothergilla in my garden, and it has been thriving. I have also seen many
of the other plants in your list growing happily in private gardens in
Seattle. Since you wish to know what they look like, here are several links to
additional information with pictures.

Hamamelis mollis picture >

Fothergilla gardenii Picture 1
Picture 2

Kalmia latifolia Picture 1
Picture 2

Actinidia kolomikta Picture 1

Picture 2

Polystichum setiferum
Picture 1 (from a local gardener)

Picture 2

protecting figs from birds

Starlings eat our figs before we can partake. Is netting the only sure solution or are there other methods?

Washington State Department of Fish and Wildlife’s Living with Wildlife page on starlings mentions netting as well as bird-scare tape and other devices. Other sources suggest picking just-ripe figs early in the morning, and not leaving ripe figs on the tree–the birds know perhaps better than we do when the fruit it ripe.

The netting is probably your best bet for the fig tree, although it is a bit cumbersome and unsightly. I imagine the figs are worth it, despite the aesthetic sacrifice.