On planting Ash trees in urban parking strips

I would like to plant several Ash trees in the border between the sidewalk and street at our home in northwest Seattle, and I would very much appreciate talking with an Ash tree expert on their recommendations. Can you help me?

I can’t claim to be an ash expert, but I may be able to find information for you about some of the trees which do well here. First, though, I need to ask you which tree you are referring to when you use the common name ‘Ash.’ Sometimes this refers to Sorbus (mountain ash), and sometimes to Fraxinus (true ash).

The City of Seattle has information about planting street trees, including lists of approved trees, trees approved with serious reservations, and trees one should not plant. (From my observations, inclusion on the list isn’t always an indication that a tree does well here. I think it is more an indication that the tree meets some criteria, such as not making excessive litter, or drastically buckling pavement.)

I can tell you from first-hand observation that the many specimens of Fraxinus angustifolia (cultivars ‘Raywood’ and ‘Flame’) are beautiful (fall color, graceful shape) but brittle in windstorms. Many were lost along the northern stretches of 35th Avenue NE during a major winter storm several years ago. Their roots may also lift sidewalks. Valerie Easton has written about these trees in her Seattle Times gardening column. Below is an excerpt:
“The beautiful flame ash trees (Fraxinus angustifolia ‘Raywood’), which are the sole reason I drive to work along 35th Avenue Northeast, are wreaking havoc with miles of sidewalk.”

Local tree expert Arthur Lee Jacobson has updated information about trees listed in his book Trees of Seattle which are no longer there:

“Green ASH. Fraxinus pennsylvanica Marsh.
The 2006 mid-December storm blew down one of 7 on 13th Ave E. It was a male. Also two of six specimens at Madrona Park went down then.

Narrowleaf ASH. Fraxinus angustifolia Vahl ‘Dr. Pirone’
The 2006 mid-December storm blew down about half on 27th Ave.”

All about Osmocote

Can you tell me what is in Osmocote? Every time I buy plants at nurseries and sales, the containers are full of these little round fertilizer pellets that get into my garden soil and never seem to decompose. Also, I try to grow organically, and I suspect this stuff is synthetic.

There are various formulations of Osmocote, marketed by the Scotts Company as “plant food.” You can look up the Material Safety Data Sheet for each of them. I looked at the MSDS for Osmocote Plus, and nothing on the product label suggests that this is a certified organic product. It contains nitrogen, phosphate, soluble potash, and various minerals. The “sources” are coated in polymer. According to this article on “PCFs” (polymer-coated fertilizers) by Douglass Jacobs, published in the 2005 USDA Forest Service Proceedings, the type of polymer material in fertilizers (such as Osmocote) varies and the degree to which the fertilizer is released will vary accordingly. Here is an excerpt:
“The coating technology in Osmocote (OM Scotts Company, Marysville, OH) was developed in the 1960s, and this coating is classified as a polymeric resin. The coating process
involves coating a soluble fertilizer core with a thermoset copolymer of dicyclopentadiene and a glycerol ester (linseed oil) dissolved in an aliphatic hydrocarbon solvent.”

I am not a chemist but if I feel I ought to be in order to understand what the polymer coating consists of, chances are good that it is not something one would want in an organic garden. Although it is written by a local gardener and not a scientist, you may find this article about polymers from Paghat’s Garden of interest. For a scientific approach, see horticulture professor Linda Chalker-Scott’s article on polymers (albeit in hydrogels, not fertilizers). Seed coatings made with synthetic polymers are prohibited for certified organic use, according to the Organic Materials Review Institute: “Prohibited when the treatments are synthetic and not on the National List. Includes all synthetic pesticides and any synthetic materials not explicitly listed, plastic polymer pelletization, and genetically modified sources of seed.” However, I was not able to find out anything about the composition of the polymer material. Seed treatment products which are “allowed” by OMRI are non-synthetic.

If you can bare-root most of your plant purchases and dispose of the polymer pellets in the trash, you may be able to avoid introducing them into your landscape. I also suggest talking to your favorite nurseries and asking them to seek more environmentally friendly alternatives.

Fertilizers, Polymer-coated fertilizer

Dog vomit slime mold

Please help me identify a killing substance in my garden that just appeared this year. I noticed it about a month ago, thinking it was animal barf. I cleared away the material and disposed of it along with the soil around it. A few weeks later I discovered yet another spot with this same substance. Upon closer inspection I found it had totally rotted my primrose and was continuing into the garden. It appears almost like a spreading mushroom with vents around it, hardens into something resembling cement, grayish white to an off yellow color. When I picked it up (with a sheet of plastic) it became brittle and released some sort of powder. Thinking it might be spores and could easily become airborne, I again bagged the material and kept it. I do not know how to contain it, or if it is hazardous to the rest of the garden. I have no idea where it came from but I do want to be rid of it.

What you are describing sounds very much like dog vomit slime mold, Fuligo septica.
See if the links below are depicting the same thing you have observed:

Tom Volk’s Fungi
Wayne’s Word online textbook of natural history, slime mold page
Mushroom Expert

Do you have wood chips or other wood-based mulch in your garden? This slime mold thrives on decaying wood. I’ve never heard of it harming plants, unless the plant matter is already decaying from other causes. I imagine it would be next to impossible to eradicate, unless you want to remove any woody material around your plants. It’s possible that extreme heat (such as fire) might kill some of the spores, but it wouldn’t be too good for your plants!

If you can tolerate it, it really is not known to devour and kill plants. Your primroses may have succumbed to something else, and the slime mold was just being opportunistic. See the following article by Kathryn Richardson, from Harvard University’s Arnold Arboretum publication, Arnoldia:

“Dog vomit slime mold is motile, but moves quite slowly. It is not harmful to animals or plants and usually vanishes in a short period of time. This species and similar slime molds feed on bacteria, fungal spores, and smaller protozoa found on wood chips. Slime molds feed much like an amoeba feeds; they ingest their food and then digest it (unlike fungi, which digest and then ingest). If conditions are favorable, these slime molds will produce reproductive structures (sporangia) that produce spores. When conditions are unfavorable (loss of food, dry conditions), the plasmodium will form hard, dormant, protective structures called sclerotia. Inside the sclerotia the plasmodium will divide into cells containing up to four nuclei. When conditions become favorable each cell will form a new plasmodium. Dog vomit slime mold is primarily an aesthetic problem in mulched garden beds. It can be physically removed, but more is likely to return. So, before panicking and taking your dog to the veterinarian, take a closer look and consider that that stuff is likely just Fuligo septica working away at cleaning the mulch.”

Myxomycetes, Quirky, Wood chips

Cinnabar moth

I have what I believe to be Cinnabar moth larvae eating my Virginia creeper. How do I get rid of them? Everything I’ve seen on the web is how beneficial they are in controlling a weed, but nothing on how to the kill the pest.

It’s interesting that there are often unintended consequences when we import insects to control noxious weeds. The cinnabar moth was brought in to control tansy ragwort, Senecio jacobaea, now renamed Jacobaea vulgaris. See the following information from Oregon’s agricultural experiment station:

“‘The cinnabar moth arrived when threats to native plants did not receive much public or scientific scrutiny,’ McEvoy said. Now a three-year survey conducted across 25 sites in western Oregon determined that cinnabar moths have been munching on arrow leaf groundsel, a native wildflower found principally in the mountains and occasionally on the coast. Scientists had thought that the places where arrow leaf groundsel grew were too cold for the cinnabar moth. But incremental climate change may raise temperatures enough to allow the cinnabar moth to thrive at higher elevations. Although the state hasn’t reclassified the cinnabar moth as a pest, the story serves as a cautionary footnote in the tansy ragwort success story.”

I don’t believe much thought has yet gone into methods for controlling the moths when they devour non-target plants. I would guess that you could attempt to look for eggs and remove them manually, or attempt to control the larvae of the cinnabar moth (Tyria jacobaeae). We can’t recommend pesticides as we are librarians and not licensed pesticide handlers, but you might investigate whether something like Btk (Bacillus thuringiensis kurstaki) is registered for controlling moths in their larval stage. Oregon Health Authority has information about Btk’s use on gypsy moth. This should give you an idea of how Btk works.

This identification resource shows images of the moth at various stages, including the eggs of the moth, so you will know what to look for.

The British web page BugLife has information on the life cycle of the cinnabar moth:
“Females can lay up to 300 eggs, usually in batches of 30 or 60 on the underside of ragwort leaves. When the caterpillars (larvae) hatch they feed on the around the area of the hatched eggs but as they get bigger and moult (instars) they mainly feed on the leaves and flowers of the plant, and can be seen out in the open during the day.
Caterpillars are feeding from July to early September and are initially pale yellow but soon develop bright yellow and black stripes to deter predators.
The caterpillars feed on poisonous ragwort leaves. The poison from the leaves is stored in the caterpillar’s body (and even remains when they are an adult moth). Any birds or other predators that ignore the caterpillars’ bright warning sign will be repulsed by how foul they taste.
Numerous caterpillars on one ragwort plant can reduce it to a bare stem very quickly. They are also known to be cannibalistic.
The caterpillars overwinter as pupa in a cocoon under the ground. The adult moths emerge around mid May and are on the wing up until early August, during which time males and females will mate and eggs are laid.”

You might also try to encourage birds in your garden, as they will eat some of the moths at caterpillar stage.

Bacillus thuringiensis, Caterpillars, Insects

T-bud grafting of maples

I have some standard Japanese maples onto which I’m trying to T-bud the weeping laceleaf maple. I’ve had pretty limited success, so I wonder if there’s something I’m doing wrong.
I’ve tried at different times of the year: late spring, summer. I cut a young small branch off the weeping Japanese maple. Then I cut off a leaf bud. I use a very thin slice under the bud, and cut the leaf off the stem. I cut the T about an inch long in the standard Japanese maple, and slide the bud in. I’ve used duct tape and plumbing tape. I don’t cover the bud but try to snug right up to it with the tape. I only get about 5-10% success doing this. Any suggestions?

You may want to consult the American Horticultural Society Plant Propagation manual (edited by Alan Toogood; DK Publishing, 1999), as it has detailed (and illustrated) information on T-budding and chip-budding. In the description of T-budding, the book emphasizes the importance of not pushing too hard into the bud. It also says to “sever the remaining tail of the bud by cutting into the bark again at the horizontal cut. Then secure the bud in place with plastic tape or raffia in the same way as for a chip-budded ornamental tree, leaving the bud uncovered to avoid exerting too much pressure on it.” Texas A & M University also has an illustrated explanation of T-budding.

According to J.D. Vertrees’s book Japanese Maples (Timber Press,2009), chip-budding is advantageous because it can be done at almost any time of year and uses less material per graft, allowing growers to make more trees with less. In any case, as long as your grafting knife is nice and sharp and you’re working carefully, don’t worry that not every graft takes. Professional propagators sometimes make four grafts expecting only one to take.

Acer palmatum dissectum, Grafting, Woody plant propagation

Drip irrigation

We are putting in a new garden, and want to install a drip irrigation system to conserve water. The area is full sun. Can you direct us to some information on systems, and offer suggestions on plants?

Here is some information from a colleague who has
experience installing and maintaining watering systems on a large
scale (at Seattle Public Library’s sites).

Drip irrigation

a sprinkler system using broadcasting spray heads is difficult to
install and wastes water; they also contribute to fungal diseases
these systems also have to be blown out in the fall (winterized)
drip irrigation is easy to install

Hints:

install after the plants are in, or place parallel lines
appropriately spaced to provide enough water while allowing for
plant root zone increase
if installed after plants are in, try to encircle the root zones
of trees and shrubs, allowing for increase in size
no need to encircle perennials; they are fine with a line on one
or both side
for such a large area, use more than one zone or there will be no
pressure (and no drip) at the end of the line
use a pressure reducer at the water source or the lines may come
apart at junctions
if on a slope, follow the contours of the slope
bury at least 6 inches so settling and soil loss do not expose
lines–and so lines don’t freeze (no winterizing)–but too deep and
you can’t tell if it’s working or not
draw a picture of the system
anchor the line with stakes (they are the shape of croquet
wickets, but ~ 4″ x 2″) and can usually be purchased with the drip
line
buy “splicing” supplies for breaks: female connectors are easier
to install and I think Netafim is the most versatile line
scheduling: staggering helps (a short watering period followed
by a long one) and remember that it has to be left on for a long
time (i.e., 1-2 hours for the long session but not every day)

Seattle Public Utilities offers the plant list and watering
guides linked here:

The Plant List

Smart Watering Guide

Soaker Hoses

Here is a guide to drip irrigation from Washington State University Extension.

I think that the best plant choices for your site in full sun will
be drought-tolerant perennials, shrubs, and trees. Here are links
to resources on selecting plants and maintaining a low-water-use
garden.

Colorado State University Extension features several links on Xeriscaping.

An article on drought-tolerant gardening by Ann Lovejoy.

Here are links to a booklist and a page of resources from the Miller Library.

You may also want to make a practice of mulching the garden to
conserve water. Excerpt from www.greenbuilder.com:

Use a deep layer of mulch in planting beds to help retain
moisture, slow weed growth, and prevent erosion.

The use of mulches on sloped areas along with terracing and
plantings can help prevent runoff and erosion problems.

Examples of organic mulch material include:

shredded bark
wood chips
pine needles
straw
pecan hulls
cotton seed hull
composted leaves
shredded cedar

The depth of mulch needed will depend on the type used. As a
general rule, the coarser the material, the deeper it should be
applied. A 3 to 4 inch layer of bark mulch should be sufficient.
Mulch needs to be reapplied as it decomposes.

The book, Water-Wise Gardening by Thomas Christopher (Simon &
Schuster, 1994), recommends matching the mulch to the planting. For
example, using pine needles around a clump of evergreens enhances
the woodland appearance of the landscape. Using organic materials
(such as compost, bark, pine needles, leaves) as mulch moderates
the access of air to the topsoil, and conserves humus. Mulch
suppresses weeds and keeps the surface of the soil from crusting
over. Ann Lovejoy’s book, Organic Design School (Rodale Press,
2001), recommends compost as the ideal mulch. Finished compost can
be pressed through a fine mesh screen to topdress ornamental
plants, while coarser compost can be used around shrubs and trees.
Compost is a feeding mulch, improving soil texture as well as
nutritional value. Here is what Lovejoy has to say about wood
by-products as mulch: “To a greater or lesser degree, most tie up
soil nitrogen temporarily as they decompose (fresh sawdust uses the
most nitrogen, while coarsely ground wood chips use the least.
Although I never use shredded bark as mulch on planting beds,
many gardeners do. It makes an attractive, deep brown mulch (that)
does not tend to rob nitrogen from the soil.” She cautions against
using thick layers of pine needles (over 2 to 3 inches) which can
get matted down and shed water instead of letting it reach plants’
roots.

Here is information from the University of Georgia Cooperative
Extension, describing the best choice of mulch for a
drought-tolerant garden:

Generally, the best mulch for the landscape is one that is
organic, fine-textured and non-matting. Examples include pine
straw, pine bark mini-nuggets, shredded hardwood mulch or cypress
mulch. Inorganic mulches, such as rock or gravel, are not good
mulches because they absorb and re-radiate heat around the plant
canopy and increase evaporative loss of water from the plant.
Fine-textured mulches, such as mini-nuggets or shredded hardwood,
do a better job of holding moisture in the soil than more porous
coarse-textured mulches.

Landscape irrigation, Microirrigation, Xeriscaping

Eliminating Algae in hydroponic systems

We recently started a hydroponic garden and currently are starting lettuce, arugula and spinach from seed. The seedlings are getting along pretty well, in spite of a mid-July start. Over the past week or 10 days there is also a considerable amount of algae growing in the water. Will this hamper the growth of the desired crop? Should we attempt to control the algae growth, and if so, how?

Algae growth is encouraged by light, so make sure your hydroponic reservoir container excludes light. Prevention is safer than treatment with algicide, which is not only phytotoxic, but not something you would want on edible crops.

Here are links which may be of interest:

Hydroponics as a Hobby, from University of Illinois at Urbana-Champaign Extension

Home Hydroponics from Virginia Cooperative Extension.

The information excerpted below comes from a now-defunct page from a home hydroponics website called Maximum Yield:

Other studies have found ‘organic’ algae control methods such as adding certain ‘grapefruit seed extracts’ to the nutrient will kill algae without harming the plants – this is a method used in drinking water, fish ponds, lakes etc. and appears to work well. There could be the potential, in larger hydroponic tanks to use ‘Barley straw rafts’ as a means of algae control as has been proven to work in ponds, lakes and other water ways. However the best method of algae control will still always be prevention of the problem, so excluding light should be the main emphasis in systems with algae problems.

Hydroponics

Vine maple roots and potential damage

I moved into a house built in 2001 on a cement slab (slab
height = 18″). Around 1 foot from my foundation is planted a Maple tree.
I have been told that it is a Vine Maple. It is around 15 feet tall. My
neighbor told me to pull out the tree because the roots will crack the
foundation of my house. I don’t want to get rid of the tree unless this
is true. I went to a nursery today, and they said that it is very
unlikely that the tree will damage the foundation (unless the foundation
is already cracked and the roots make these cracks worse). What do you
think? I have no idea if the foundation has cracks that the tree could
exacerbate or if a Vine Maple in general would crack a foundation like
this.

I do think that planting anything one foot or less from the house is not
ideal, especially a tree. However, vine maple roots have a low potential
to cause damage, according to the database of the Urban Forest Ecosystems
Institute (see full tree record for Acer circinatum).

On the question of how close to a house a tree can be planted, I found
the following from New Mexico State University Extension site, in answer
to a question like yours about root damage potential:

“A more important consideration is keeping the branches from rubbing
against the house and damaging the stucco, siding, or paint and shingles.
By planting the plant a distance greater than the expected mature crown
radius from the house, you will avoid damage to the house by branches.
You will still benefit from shade if the tree is properly positioned.

“Many trees are planted so that their branches are trimmed to be higher
than the roof and then grow over the roof. Remember, if one of these
large branches breaks in a wind storm, it can damage the roof, so
distance from the house is the best protection from such damage. Learn
how widely the branches spread from the trunk when the tree is mature and
plant at least that distance from the house. Yes, you can break this
rule-of-thumb, but the hazards increase when you do.”

You may want to consult a certified arborist to evaluate the situation,
and see if you can keep the tree where it is. To find a certified
arborist, contact Plant Amnesty or the Pacific Northwest Chapter of the International Society of Arboriculture.

Acer circinatum, Tree roots

Fraser fir with rusty tips

We planted a young Fraser fir last March. It has a lot of
new growth, but has developed some dead-looking tips here and there that
are a reddish rust color. I am wondering if we have a serious problem or
should I just remove the affected tips and not worry about it? I have
noticed a lot of trees this summer on my travels out through the
Cumberland-Enumclaw area that look a similar cinnamon color and are
totally dead!

The problem you describe could be the result of drought injury, or it
could be one of several rust and fungal diseases which affect fir trees.
Was the tree watered well after planting? Here is information
on drought injury from Oregon State University’s plant disease database. Excerpt:

Drought injury usually progresses from the top of the tree downward and
from the outside to the inside of the crown. Top dieback and branch death
may be common. Defoliation of the mid-crown or loss of needles at the
base and tip of shoots can also occur in Douglas-fir. Older needles
commonly turn yellow and are shed prematurely. Roots may be alive even
though the entire above-ground parts are dead. Winter injury, gopher and
root weevil problems can produce similar symptoms.

Your description also sounds like the symptoms of Phytophthora, a fungal
disease which is common in our area. Excerpt:

Phytophthora root rot is usually a problem only in areas with poor
drainage or where flooding occurs. The fungus attacks the roots, which
rot and die. The infection moves up into the crown, where the cambium
(soft inner bark) turns reddish-brown or caramel in color instead of the
normal white to greenish color. Older trees may develop cankers on the
trunk, which are a dark reddish-brown when cut. The cankers may be
accompanied by split bark and oozing pitch. Lower branches wilt, turn
dark red, and die back. Younger trees are often killed outright, while
infected mature trees may show wilting, branch dieback, and/or gradual
decline.

Missouri Botanical Garden’s Integrated Pest Management site has information and includes an image of Fraser fir suffering from Phytophthora.

The Pacific Northwest Pest Management handbooks have a section on diagnosing and controlling phytophthora diseases.

I recommend taking a sample of one of the cinnamon-colored branches to a
Master Gardener Clinic, and also taking photos of the whole tree, so that
you can have the problem diagnosed. If you are near Enumclaw, the Pierce County Master Gardeners offer diagnostic clinics.

Abies, Trees–Diseases and pests

Edible flowers for wedding cakes

I am planning to decorate my wedding cake with Alstroemeria. Are these flowers safe to use? The flowers won’t be eaten, but will be in contact with the icing.

The website of National Sustainable Agriculture Information Service has a page of resources on edible flowers, including links to information about toxic plants. Alstroemeria can cause contact dermatitis when handled, and ingesting the plant can cause gastrointestinal problems. See the following information on Alstroemeria from North Carolina State University Extension.

Rather than take any chances, I recommend restricting your decoration choices to
edible flowers. A mixture of calendula, lavender, and violet blossoms, for
example, might be an attractive option. North Carolina State University Extension also has an article on edible flowers.

Iowa State University Extension has useful guidelines on selecting edible flowers.

Alstroemeria, Edible flowers, Poisonous plants