controlling apple anthracnose

Can dormant oil or lime sulfur sprays help to control or prevent apple anthracnose? Is there any other way to prevent it besides cleaning up old leaves and disinfecting pruning tools between trees?

There are varying opinions on the best approach to controlling apple anthracnose (Cryptosporiopsis curvispora). British Columbia’s Agriculture Department suggests that cultural controls (i.e., good garden hygiene) are key, and fungicides have proven ineffective. Here is an excerpt:
“Spores from new cankers are spread by rain or overhead irrigation during the late summer and fall months, and initiate new infections that appear as cankers during April through July of the following year. Cankers that are allowed to overwinter produce airborne spores during the following spring and summer that can initiate new infections at a distance from the source. The airborne spores function mainly to initiate new infections, while the water-borne spores serve to intensify the disease in trees that are already infected.

Cultural Control:
Prune out and remove all cankers during winter pruning. Prune out any new cankers that develop on limbs and trunks as soon as they are discovered, and remove them from the orchard. Developing cankers often girdle 1-year-old wood; remove any shoots that wilt or die suddenly during April through July as soon as they appear.

Nursery trees should be examined carefully for symptoms of the disease at planting and again the following spring. Trees with cankers should be returned to the nursery for replacement or discarded.

The cultivars Elstar, Empire, Gala and Sinta are very susceptible to anthracnose canker.

Chemical Control:
There are no fungicides registered for control of anthracnose and perennial canker in Canada, and fungicides have not proven to be effective.”

Although Oregon State University’s Online Guide to Plant Disease Control lists several chemical controls, they too indicate that chemical control alone is ineffective.

According to The Apple Grower by Michael Phillips (revised and expanded edition, Chelsea Green, 2005), anthracnose typically follows environmental stresses like cold, drought, or pruning injury. The best control is removing and burning infected parts of the tree. “Bordeaux mixture applied immediately after harvest and again two weeks later can help prevent spore germination in orchards with a severe problem. Any developing cankers the next growing season can be roasted alive using a propane (plumber’s) torch.”

I’m not sure if you feel comfortable getting out the blowtorch. Bordeaux mixture is one type of lime/sulfur combination, and it has its risks (to plants, the environment, and health), and possibly only limited benefits. Below is more information about this from
University of California, Davis Integrated Pest Management.

transplanting Embothrium seedlings

We had a lovely Embothrium coccineum for about 15 years. Last year we had our Chilean Fire Bush removed and the stump ground after the wind blew over the tree. That was a great loss because we loved the tree. Now I have six new starts of Chilean Fire Bush ranging in size from one to three feet, which I assume are growing off a live root. I’d like to transplant them to more appropriate places in my yard, but the buyer at a local nursery advised against moving them. What can you advise me about transplanting? Is fall even the right time of year to move them? How deep can I expect the roots to go?

The people at the nursery may be thinking of Embothrium’s reputation for resenting transplanting. According to Graham Stuart Thomas’s book, Ornamental Shrubs, Climbers, and Bamboos (Timber Press, 1992), Embothrium coccineum seldom thrives when transplanted. However, I think he is talking about the difficulty of transplanting a mature tree, not a small seedling. Simon Toomer’s Trees for the Small Garden (Timber Press, 2005) confirms this: “It has a reputation for being difficult to transplant when large and so container-grown plants of moderate size should be used.”

Local gardening expert Ciscoe Morris has said of Embothrium: “Only buy it if it’s a small seedling. They hate pots and if they are pot-bound for very long, won’t survive transplanting. Plant Embothrium in a sunny location in acid very well-drained soil. Never fertilize these trees as phosphorus is known to kill them.”

Since you have several starts, why not try transplanting at least one or two of them to an ideal spot in your garden. Try to get as much root system as you can when digging them up, and if more than one start comes up, don’t try to cut them apart if it means you will lose any roots. Now is probably a good time to attempt this, and there is not too much risk in trying.

Salvia sclarea and its invasive potential

I bought a plant at a local plant sale, Salvia sclarea ‘Turkestanica’. As I was researching the plant online, I saw several nurseries stating that the plant can’t be sold in Washington State. Am I right in thinking that this is an invasive species? Is it safe to plant in Seattle?

You are correct about its invasive potential. Clary sage (Salvia sclarea) is a Class A noxious weed and cannot be legally sold in Washington, since at least 2003. Eradication of Class A weeds is mandatory. I imagine that the seller was unaware of its status in Washington. Here is more information from the King County Noxious Weed Control Board.

According to the USDA’s Germplasm Resources Information Network, Salvia sclarea ‘Turkestanica’ (or turkestaniana, as it is spelled here) is a synonym for Salvia sclarea, so it would not be exempt from the weed regulations.

planting and caring for new Magnolia trees

How do I go about planting a new Magnolia tree this fall?

The City of Seattle’s Department of Transportation has perhaps the best set of instructions and tips for planting trees in the Pacific Northwest. It includes a diagram of how to plant a tree. This same site also has guidelines for care of young trees.
If your tree is a “street tree” (planted in a parking strip), then be sure it is appropriate. The left-hand menu here gives lists of trees that are and are not appropriate, under Street Trees.

The current consensus is that you do not need to amend the hole with new or superior soil from another source when you fill in the hole, as this just creates an environment the roots do not want to leave. In order for a tree to become established, the roots need to grow outward, into the native soil. Washington State University Extension professor Linda Chalker-Scott discusses this subject as well as whether or not to disturb the root ball, how to handle balled and burlapped trees(remove the wire basket!), and whether staking is necessary.

The University of British Columbia Botanical Garden Forums includes the following comments about planting some varieties of magnolias:

“I would only use a well seasoned compost for a Magnolia as a top dress at planting time. We advised people to dig the hole three times the width of the root ball and place the dug out soil back in the hole with no other soil additives. Providing a root shock preventer such as liquid Vitamin B1 at a rate of one fluid ounce per gallon of water is optional. A good choice to use when planting these Magnolias on a warm day in a warm climate but generally not needed in the Pacific Northwest. What we have to guard against is planting this and others of this series too low in the ground. We like to plant these in a raised mound for a yard planting. Never plant these trees with the graft union at soil level, try to plant them about six inches to a foot above the soil level and allow
for settling in later. A Spring planting is regarded as being best for these Magnolias but in the warmer climates can be planted almost year round as our soils here seldom ever
are frozen.”

I would add to this that planting too deeply is a common mistake, but another mistake is to plant “too high” (as is suggested above, when the writer mentions planting in a “raised mound”). Some people think that such a mound can be buried in mulch; it is much better to plant at the proper depth and use mulch from about 6 inches away from the trunk to the outer edge of the root ball, creating a ‘dam’ as described by Seattle Department of Transportation.Then you can turn the hose on low and let the water fill the ‘moat’ created by the dam. During the winter, be careful that your mulch is not too deep, as it can actually keep water from getting into the soil (3-4 inches of mulch is plenty). Mulch in the spring through fall is much more important for keeping water from evaporating from the soil surface, as well as for slowing down the weeds. Be careful not to pile mulch against the trunk of the tree, as this can cause rot.

One more thing, as mentioned below on University of British Columbia Botanical Gardens Forum, do not fill the planting hole with water, as this may contribute to root rot.

growing herbs indoors

I want to grow herbs indoors, especially over the fall and winter. Can you recommend some good books, and tell me how to get started? What’s the minimum temperature for growing them?

One of my favorite general books on growing herbs is by a Seattle gardener and author, Mary Preus, entitled The Northwest Herb Lover’s Handbook (Sasquatch Books, 2000), but there is limited information on growing them indoors. Another book, The Edible Indoor Garden by Peggy Hardigree (St. Martin’s Press, 1980) includes a section on herbs to grow as well. Most of the herb gardening books discuss bringing culinary herbs which have been growing outdoors inside during winter, when it is less possible to grow them outdoors. According to Patrick Lima, author of Herbs: The Complete Gardener’s Guide (Firefly Books, 2001), “a thriving indoor herb garden depends on good sunlight–a sun room, greenhouse or large south-facing window–but many herbs need winter rest. Obvious choices for wintering indoors are tropical herbs or Mediterranean plants–fruit and pineapple sage, scented geranium, rosemary, bay…” The best choices for fresh winter use are basil, parsley, tarragon, oregano, the mints and hardy savories, chives and garlic chives, rosemary, tropical sages, lemon verbena, and scented geranium.

The National Gardening Association has useful information on indoor herb gardens. Here is another article from the same site.
This gardening blog focuses on using recycled containers, such as growing herbs in old dresser drawers (but make sure not to use furniture that may have been painted with lead-based paint!).

This University of Missouri Extension link (now archived) has a useful guide to indoor herb gardening, excerpted below:
“Growing herbs indoors by Kathryn Keeley,MS,Former Horticulture Specialist

In 1652, Nicholas Culpeper wrote The English Physician, which combined the folklore and traditional medicine that surrounded herbal usage during that time. Colonists in North America consulted this book as a medical reference. Herbs served a variety of functions in the pioneer home, including curing illness and disease, dyeing fabric and repelling insects.

Today, consumers are turning to herbs for increased health and vitality, as well as for more domesticated duties such as decorating and cooking. A perfect way to get the taste of summer is by growing herbs indoors during the cold months. Here are a few tips if you’d like to grow your own herb supply:

Light source. Perhaps the greatest challenge when growing herbs indoors is providing them with sufficient sunlight. Herbs do best when grown in a very sunny window that receives between six and eight hours of direct sunlight each day (typically a southern or southwestern exposure). When growing herbs under natural light, be certain to rotate the pot every three to four days to ensure uniform growth of the plant.
If your most convenient window location does not have enough sunlight you can supplement natural lighting with fluorescent light. In general, for every hour of required sunlight expose the plants to two hours of fluorescent light. Herbs grown entirely under fluorescent lights will require between 14 to 16 hours of artificial lighting. Place herb plants no closer than five or six inches and no farther than 15 inches from the light source.
Drainage. Herbs demand good drainage for healthy growth. A potting mix of equal parts sand, commercial potting mix, peat moss and perlite will provide an excellent medium for growing herbs indoors. When potting your herbs, choose clay pots. They are more porous than plastic pots, allowing for better soil drainage.
Temperature. Be certain not to locate your indoor herb garden near a heat source, such as a radiator or heat vent. Herbs prefer temperatures below 70 degrees. If the air is dry in your home, place the herb pots in a tray of stones and keep the tray filled with water just up to the bottom of the pot. Providing ample humidity will promote good herbal growth while keeping the foliage succulent and tasty.
Fertilizer. When grown in containers, most herbs will benefit from occasional feeding with a liquid fertilizer, such as fish emulsion, seaweed or a general-purpose, water-soluble fertilizer. In general, feed herbs every two weeks according to the manufacturer’s instructions. Be certain not to overfeed your herbs. Too much fertilizer is far more likely to damage your herbs than too little.
Herb types and use. Chives, Thyme, Basil, Parsley, Rosemary, Sage, Oregano and Mints all do well indoors. Use them regularly to keep them trimmed back and prevent flowering, which will reduce the plant’s longevity.

on harvesting sassafras bark for tea

When and how do I harvest bark from my Sassafras tree to make tea?

I would suggest proceeding with extreme caution, and talking to your physician before endeavoring to make sassafras tea. According to Medical Botany: Plants Affecting Human Health by Walter Lewis (Wiley, 2003), the active component in Sassafras albidum, safrole, is no longer generally regarded as safe. It is toxic to the liver and can cause cancer. There is information on sassafras here from the Natural Medicine Database. A now-unavailable article on the U.S. Food and Drug Administration website included this description of sassafras as a tea ingredient:
“Aromatic sassafras tea, once popular as a stimulant and blood thinner and as a reputed cure for rheumatism and syphilis, causes cancer in rats when taken in large amounts. Oil of sassafras and safrole, major chemical components of the aromatic oil in sassafras root bark, were taken out of root beer more than 30 years ago. And sassafras bark was banned from use in all food. Safrole-free extract, however, is allowed in food.”

Although historical sources may discuss the best time to harvest parts of the Sassasfras plant for medicinal uses, I would recommend against using it for this purpose, given the associated health risks. Tyler’s Honest Herbal by Steven Foster and Varro Tyler says that the root bark was used as a febrifuge prior to 1512 by native dwellers in Florida. The fact that its reputation for usefulness persists is mainly due to its pleasant aroma and flavor, but the authors make clear that it is unsafe.

You are welcome to come in to the Miller Library and explore our resources on medicinal plants and herbs, but I would not advise you to follow any recipes you might find there.

managing deer around your garden

How can I keep deer out of my garden? Something is eating my plants, and I think it’s deer. Do they like dahlias? Those are my favorite, and they seem to be especially hard hit. They don’t seem to like it when we water, so maybe we could do something with that?

Deer are very hard to repel. Information about managing deer around your home and garden is available at the Washington Department of Fish & Wildlife site, Living with Wildlife. (There are no guaranteed or complete repellents. As the link above mentions, some of the repellents may be toxic to plants, and may not be effective for very long. Furthermore, some of the predator urine repellents may not be humanely produced.)

First, you should identify which plants are being eaten; rodents and rabbits make a clean cut, while deer leave a jagged edge. And, of course, the browse marks are higher up on the plants if deer are the culprits. Fortunately, most native plants can survive some browsing. Unfortunately, deer do eat dahlias.

Once you determine which plants the deer is eating, you can often protect just those plants with a 4-6 foot circular fence just around the base of the plant. If you are trying to protect a small vegetable garden, you might be able to fence and cover it (suspending netting or chicken wire from the tops of the fence posts) as well. Fencing material can be made of woven wire or rigid polypropylene mesh.

You might consider motion-sensitive sprinklers, lights, or a radio–you did say that water scared off the deer. Some people have used blinking lights with success, strung so that they cast many shadows.

Some home remedies will work some of the time, though none work all of
the time. And, they all have to be replenished after a good rain or
watering. Here are some anecdotal examples of things that have worked (taken from
Washington Department of Fish & Wildlife biologist Russell Link’s book, Landscaping for Wildlife in the Pacific Northwest, 1999):

Keeping dogs near the plants (for instance, installing their run near the garden).
Human hair, strong-smelling soap, or
blood meal placed in stockings or cheesecloth bags and hung near the
plants.
Several old eggs blended in a gallon of water and placed in vented
containers, hanging near the plants.

The Washington Department of Fish & Wildlife’s Living with Wildlife website includes Link’s list of plants that are at least somewhat
deer-resistant. There are lists from Oregon State University and the King County Native Plant Guide, too.

While you may have to put up with some damage, I hope the ideas above will give you some places to start.

music and plant growth

How does music affect plant growth?

Washington State University professor of horticulture Linda Chalker-Scott
uses the example of a book on the effect of music on plants as an instance
of ‘bad science’ in one of her articles. In other words, the idea is not based on repeated
experiments, and has not been put to the test of attempts to prove or
disprove it. Many student science fair projects pursue this question. There are many other scientists discussing this, and sites on the topic, too.

The TV show Mythbusters Episode 23 has dealt with this question.

There are also two questions exploring this at the MadSci network, a scientist-staffed question site. Here is an excerpt from the MadSci network’s discussion:

Experiments on the effects of sound or music on plants are very difficult
because you need a lot of replication (number of plants for each
treatment) and
identical environments for each treatment other than the music or sound
level.
That is difficult to achieve even for a professional botanist much less
in a
home or classroom. You also need a statistical analysis to determine if
the
growth differences are real or just due to natural variability. No
botanist has
yet found a beneficial effect of music or sound on plant growth that is
reliably repeatable and statistically significant.

The idea that plants grew better with certain kinds of music apparently
arose in the best selling book, ‘The Secret Life of Plants.’ That book
was filled with incorrect information. Botanists have failed to find that
plants grow better or worse with a particular type of music or that music
has any effect on plants.
While the stories in ‘The Secret Life of Plants’ are intriguing, they are
not based on careful scientific experiments. For accurate scientific
details on plants try a college botany textbook (Stern, 1991) or popular
books on plants written by scientists (Attenborough, 1995; Wilkins,
1988).

Reference:

Attenborough, D. 1995. The Private Life of Plants. Princeton, NJ:
Princeton University Press.

Stern, K.L. 1991. Introductory Plant Biology. Dubuque, Iowa: Wm. C.
Brown.

Wilkins, M. 1988. Plantwatching: How Plants Remember, Tell Time, Form
Relationships and More. New York: Facts on File.

Professor Ross Koning, who teaches Plant Physiology at Eastern
Connecticut State University has addressed this question at length, too. Here is an excerpt from that site (now archived), as well:

“If plants don’t have music appreciation, do they respond to sound?
It is possible for a plant to respond to the vibrations accompanying
sounds. A short bibliography at the bottom of this page gives you some
references…but to almost ‘nothing to report.’ I emphasize again that
while there ARE responses to sound/vibration in plants, there is NO
controlled study published on the MUSICAL TASTES or MUSIC APPRECIATION by
plants in reputable journals.

One plant that responds to sound-induced vibration is Mimosa pudica, also
known as the ‘sensitive plant.’ Vibrations induce electrical signals
across the leaflets of this plant, and cells at the base of the leaflets
respond to these action potentials osmotically. This response results in
a sharp change in the turgor pressure in these pulvinus cells, and that
pressure change, in turn, results in the folding of the blade at the
pulvinus. Another pulvinus at the base of the petiole may also respond if
the vibration is severe enough. This kind of response is known as
seismonasty.

How would this plant respond in terms of growth if its leaves were kept
closed by constant vibration? If you think very long about photosynthesis
in leaves as the driving force for growth, you will realize that
continuous leaflet closure would inhibit rather than stimulate the growth
of the plant. Indeed loud sounds (vibrations really) have been reported
to negatively impact plant growth (reference below).”

cause of red leaves in rhododendrons

I have some native rhododendrons that have tan or reddish leaves every spring. The red leaves are new leaves, and they are red for about two weeks. They are under some 100 year old Douglas fir trees, and get some shade and some southern light. They were moved to my garden from and altitude of 4000 feet to my altitude of about 1850 feet. What causes the red leaves?

New red shoots and bronze leaves are not uncommon in Rhododendrons. In fact, some are grown purposely for their colorful new growth. The creator of Paghat’s Garden, a local website writes enthusiastically of a Rhododendron ‘Hill’s Bright Red’:

“When it is first finishing with its bright red blossoms, it begins producing new leaves, that are at first bright red themselves! …The new red leaves mature to green..”

She also has written specifically about the Pacific rhododendron, Rhododendron macrophyllum.

As to why this coloration sometimes happens, it is possible that the reddish-brown pigment seen in young [Rhododendron] leaves
affords tender foliage some protection from sunburn. This is important because too much ultraviolet radiation can destroy chlorophyll in plant
leaves. Plants avoid getting too much UV radiation by producing red pigments called anthocyanins, which can absorb UV radiation and thus prevent it from damaging other parts of the leaf. Because
the pigment “accumulates in the cell sap, and is usually located in the
epidermal and subepiderma cells,” its presence vividly changes the color of the
leaves (Levitt, p. 294). This, and more information about anthocyanins is available in a book available at the Miller Library called Responses of Plants to Environmental Stresses, volume 2, by J. Levitt (New York:
Academic Press, 1980). In effect, your plants are producing their own sunscreen for the tender new
growth!

You can also find more information about anthocyanin in the article “Nature’s Swiss Army Knife: The diverse protective roles of anthocyanins in leaves,” by Kevin S.
Gould, hosted by PubMed Central.

Ilex crenata and cross-pollination

I want to be sure to get berries on my (female) Ilex crenata convexa
so went looking for male Ilex crenata cultivars. It is not that easy.
So my question is: will Ilex species pollenize each other? For example, I have
a big male holly tree (Ilex aquifolium) close by, will that pollinate the
female Ilex crenata convexa?

The best berry production will come from planting a male and female of the
same species, but you can sometimes get away with using a different
species as long as both the male and the female plants are the same type
of Ilex (that is, both deciduous or both evergreen) with the same
(potential) color berries (red or black-berried species). Also, you want
two plants which flower at the same time.

Ilex crenata potentially produces black fruit. Ilex aquifolium produces
red fruit, so this would not be a good match. I. aquifolium is also
considered an invasive species in our area.

This link to a page from Clemson University Extension, describes various species and cultivars of Ilex. Ilex glabra is another species which produces black fruit.

There are some male cultivars of Ilex crenata, such as ‘Green Dragon,’
‘Hoogedorn,’ ‘Nigra,’ ‘Rotundifolia,’ and ‘Beehive.’

According to the website of a local gardener, there are other hollies
which will cross-pollinate with Ilex crenata, but she does not specify
which ones.

You are in good company in your quest for male Ilex crenata
cultivars–a local (Seattle) garden writer had a very similar question
recently. I hope you are able to get berries on your plant–you could try
waiting to see if perhaps you do get fruit (if there are other hollies in
the neighborhood), and then mail-order a male specimen or ask your
favorite local nursery if they sell any of the varieties mentioned above.