lawn alternatives and planting under pine trees

Our house is on a corner lot. The side yard has a very small slope with big rocks along the edge. Presently it has a variety of flowers such as lavender that bloomed last summer.
However, my question is what kind of ground cover can I put there, other than grass, that would look good and be evergreen.

Secondly, there are two big pine trees at the corner. What are my options for plantings beneath these trees that would give it a pulled-together look?

I am guessing that the spot receives a good amount of sun, since you have lavender Lavandula that flowered there in the summer. Were you looking for a groundcover that will tolerate people walking on it, or did you want somewhat taller plants that will blend well with the lavender?

If you plan to walk on the area, you might want to consider chamomile (Chamaemelum nobile) or creeping thyme (Thymus serpyllum).

There are many great choices for plants not intended to be walked on, and I recommend that you take a look at some of the resources we have in the Miller Library so you can find the plants that most appeal to you. I recommend the books Gardening with Groundcovers and Vines by Allen Lacy (HarperCollins, 1993), and Perennial Groundcovers by David MacKenzie (Timber Press, 1997) as starting points.

Plants that are evergreen (or ‘ever-grey’) and might go well with lavender are Santolina, Helianthemum (sun rose), Teucrium chamaedrys (germander), and Ceanothus thyrsiflorus (creeping blue blossom ceanothus).

For the spot under your pine trees, you will need plants that tolerate shade and do not have large root systems. I would try Lamium (dead nettle), which comes in several foliage and flower colors, and I would avoid Lamium galeobdolon, a species which is considered a noxious weed in King County. Vinca (periwinkle) might also work. The Lady Bird Johnson Wildflower Center has information on planting beneath pine trees.

adjusting pH in hydroponic systems

What are the disadvantages of using white vinegar to lower the pH in my hydroponic system?

I have read that I should use phosphoric acid. But I have also read that phosphoric acid could be bad for hydroponic systems with hard water. I am using well water with a starting pH just below 8.

I also heard that nitric acid would be good for hard water but that the acid may be too aggressive for most novice users.

Here is general information on growing hydroponically from Virginia Cooperative Extension:

Hydroponically grown plants must obtain all their nutrients, including trace elements, from the nutrient solution. Success or failure may depend on precise and complete fertilizing practices. Complete nutrient solutions, specifically made for hydroponics, take the guesswork and the mess out of mixing one’s own formulas. All hydroponic nutrient solutions must be changed after a short period since evaporation causes concentration of salts in the water. Adding fresh solution to old solution would only make things worse. During spring and summer, pour spent nutrient solution around trees and shrubs.

Here is information from www.oswego.edu on adjusting pH in your hydroponic solution:

* The pH value refers to the acidity or alkalinity of the nutrient solution.
* pH readings run from 0 to 14 (0-6 acidic; 7 neutral; 8-14 alkaline).
* The recommended pH level for a general hydroponic solution is between pH 6 and pH 6.5. (Nicholls, 63)
* Many different variables can effect the pH level.

o Temperature
o Amount of light
o Evaporation
o Tap water refining
o Amount of nutrients

* With this amount of variables, periodically checking the pH level of the solution is vital to maintain a healthy environment for the growth of the plant

* Adjusting the pH level of the nutrient solution can be done simply.

o If a solution is too acidic, add one tablespoon of baking soda to three gallons of solution.
o If a solution is too alkaline, add one tablespoon of white vinegar per four gallons of solution.

This link to Texas Agricultural Extension Service addresses growing vegetables hydroponically, and offers details about nutrient solutions:

The book, Home Hydroponics…and How to Do It by Lem Jones (Crown Publishers, 1990) suggests testing the salt content of your water. Since you are using well water, you would need to contact the State Water Board (here is a link to Department of Ecology’s Water Resources page).

If the total amount of dissolved salts in your water is less than 700 ppm, the water should present no problem. This same resource says that a pH of 5.8 to 6.2 should be good for most plants. Since your pH is alkaline, you will need to acidify the solution. For adjusting a few gallons of solution, two regular aspirin per gallon of water will lower a pH of 8.0 to near 6.0. You can use a teaspoon of white vinegar per gallon as an alternative method. In a large system, this book recommends using sulphuric acid, but protect yourself from acid splashes and always pour the acid into the water and not the water into the acid.

The book Hydroponics for the Home Gardener by Stewart Kenyon (Key Porter Books, 1992), confirms the above, but remarks that vinegar is only a temporary measure and its effects will not hold for more than a few days. The author recommends using phosphoric acid, which he says is nearly harmless–just be sure to wash any spills off yourself right away with baking soda and water. If you add 0.1 millilitres of phosphoric acid per one gallon of water with a pH of 8.0, and a hardness factor of 136 parts per million, the pH should be reduced to 6.8.

Acer palmatum cultivars for full sun

I want to find an Acer palmatum cultivar
that can manage full sun and high winds. Is this asking too much of the
dainty thing? Can you suggest a type, or a source that lists palmatums
and their various needs and attributes?

The main issue with Japanese maples and wind would be hot, drying winds. According to this information from University of California Master Gardeners, sunburn can be a problem, and hot wind exacerbates it: “Leaf scorch can appear on any type of deciduous tree, shrub or plant. During prolonged periods of drought, windy weather or bright sunshine, Japanese Maples are particularly susceptible, especially young trees.”

I would be concerned about scorching from exposure to hot wind, and
damage from winter wind even if the tree is not likely to lose limbs.
Here is what J. D. Vertrees’s book, Japanese Maples (Timber Press, 2001,
3rd ed.) has to say: “A spot with a constant strong wind will misshape the plant and may burn the leaves. In winter, the wind-chill factor may cause bark and cambium
damage (…) In areas of strong marine breezes, leaf damage from salt
deposits may occasionally occur. Anyone growing plants under such
conditions should be familiar with the necessary protection and the need
for periodic washing of the foliage with fresh water.”(p. 63)

A commercial nursery, Maple Ridge groups Acer palmatum cultivars by type. University of British Columbia Botanical Gardens offers additional information.

Cross orbweavers in the garden

I just saw a ball of tiny yellow spiders with black dots clustered on the end of a Santolina stem. Are they beneficial in the garden, or should I remove them?

Your description sounds like the cross orbweaver (also called cross spider, because of the white markings on the back of its abdomen), Araneus diadematus. Its baby spiders (spiderlings) are yellow with black markings, and they crowd together and seem to move as one if disturbed. They hatch (in groups of hundreds to almost a thousand) from a fluffy-looking pale yellow egg sac. The Washington NatureMapping website has a factsheet about this species.

These industrious spiders build a new web each day (after eating the previous day’s web). They are often found close to houses and illumination (at my house, the nests appear behind the porch light) and in gardens. Their diet consists of invertebrates, so in that sense, they do provide some benefit in the garden.

Cross orbweavers in your garden are not a problem, though humans occasionally encroach on their space, and the spiders may bite in reaction to the disturbance. Some people are more sensitive to the bites than others. My strong recommendation is to let them be, and enjoy observing them.

on pruning sedges

The Carex buchananii in my parking strip garden is now large enough that it’s reaching out over the sidewalk and getting underfoot. Can I safely cut it back? Can it be cut to the ground in spring and allowed to start over?

Sedges like yours should not be cut back too far. The magazine Horticulture says you can “gather up the leaves in one hand and, using a pair of scissors, cut off the top third, including the long flowering stems. This will leave the plant arching out gracefully, but not trailing along the ground. It may be necessary to do this twice a year: at the beginning and end of the summer.”

Val Easton, writing in the Seattle Times (October 8, 2008) says “sedges resent being cut back too hard, so if the foliage lasts through the year untattered, just leave it alone. If the older foliage looks messy, or the tips have been burned by winter cold, trim the sedge back modestly, by no more than a third at most, in March or April.” Another thing you could do is to dig up and divide your Carex in March, and move it away from the edge of the planting bed.

on testing vegetable garden soil

I would like to know if there is some place where I can have my vegetable garden soil tested. For the last two years my vegetable plants were abysmal except for tomatoes and lettuce.

The Natural Lawn & Garden Hotline, sponsored by Seattle Public Utilities, provides the following recommendations on how to take a soil sample:

1) Take about 10 vertical slices of soil from the top 6-8 inches of your garden bed. If there is an area that you suspect to have problems, test this soil separately.

2) Place soil slices in a plastic bag and mix thoroughly. You are getting the average of the soil in your garden bed.

3) Take 1 cup from this mixture and dry it at room temperature. Do not dry in oven, on radiator or in microwave!

4) Put dry soil sample into a Ziploc bag and seal.

5) Label the outside of the Ziploc bag.

6) Mail to one of the soil testing labs below with completed order form and payment.

A WSU has a publication on soil testing for vegetable crops but it is mainly for agricultural growers.

Another option is the University of Massachusetts, Amherst soil testing laboratory.

This page has information and forms to send in with your samples.

For testing of toxics see:
King County’s Resident Self-Testing Page.

A & L Western Laboratories, Inc. in Portland, OR can provide soil and plant analysis.

Russian sage or Siberian lavender

I am looking for rare Siberian lavender. Can you help?

I think what you mean is Russian sage, Perovskia atriplicifolia. You might want to phone your favorite retail nursery to see whether they carry it (it is very popular). If it is not available, here are two Oregon nurseries that list it in their current catalogs:

Forestfarm in Williams, OR.

Joy Creek Nursery in Scappoose, OR

The following article (now archived) from University of Illinois Champaign-Urbana Extension describes the confusion between Russian sage and ‘Siberian lavender:’
“To the best of my knowledge, there is no such plant as Siberian Lavender. I have heard of English lavender, French lavender and Spanish lavender. By law all of these offers must list the Latin name of the plant; although sometimes it is in the tiniest of print. Check the ad again and see if you can find the words Perovskia atriplicifolia anywhere in the ad. Russian sage. It is a really fine plant, but it is not lavender. It does not look like lavender and it does not smell like lavender.

Do your homework and read the fine print. I know many people are not familiar with botanical names, but that is the only way to know what you are getting. Once you know the botanical name, even if you cannot pronounce it, you can find information about the plant. Botanical names are unique. Common names can be very misleading.
A good example is an ad I saw recently in the newspaper. It was touting the luxurious beauty and fragrance of Siberian lavender. I had never heard of anything called Siberian lavender so I kept reading. The ad stated (with lots of exclamation points) how Siberian lavender produces thousands of flowers and has the delicate scent of lavender perfume year after year. Wow, sounds pretty fantastic. I continued to look to find the botanical name. In the minuscule fine print it said, Variety: perovskia atripliafolia (which I assume to be the misspelling of Perovskia atriplicifolia) also known as Russian sage. Russian sage is a nice perennial plant with silvery white leaves and soft bluish-purple flowers held in loose spikes. However, even from far away on a foggy day I doubt Russian sage would hold even a slight resemblance to lavender. Russian sage does have a fragrance, but it is more reminiscent of sage than of lavender.”

powdery mildew resistant dogwood hybrids

Where can I find information about dogwood hybrids, especially crosses between Cornus kousa and C. florida? Won’t these trees be more resistant to the mildew affecting many dogwoods?

In addition to powdery mildew, many dogwoods can suffer with anthracnose. In his book Dirr’s Hardy Trees and Shrubs (Timber Press, 1997), Michael Dirr mentions Rutgers Hybrids (which are a cross of the kousa and florida species of Cornus). These trees were developed at Rutgers University by Elwin Orton, and are resistant to dogwood anthracnose. This article from North Carolina State University Extension discusses powdery mildew resistance. Scroll to the second table at the end which charts cultivars and their resistance or susceptibility to powdery mildew.

Oregon State University provides information about each of the six hybrids of C. florida x C. kousa. Two of the trees on this list are resistant to powdery mildew.

Clemson University Extension offers further information about the insects and diseases affecting dogwoods.

best tomatoes to grow in the PNW

What are the best types of tomatoes for the Pacific Northwest climate?

In Growing Vegetables West of the Cascades (Steve Solomon, 2000, pp.241,242), the author notes that any tomato advertised in a seed catalog as needing more than 72 days for maturity will not likely reach a ripe old (tasty) age in our region. Solomon suggests purchasing seed only from regional companies like Territorial Seed Co. or West Coast Seeds. The varieties he recommends are
1. some that ripen early in the Willamette Valley (bred by Jim Baggett) = Oregon 11, Oregon Spring, Santiam, and Gold Nugget
2. slicers = Fantastic Hybrid, Pic Red, Early Cascade, and Kootenai
3. cherry = most are prolific here, but Solomon prefer’s Jim Baggett’s Gold Nugget

Here is a link to an article by Chris Smith in the Seattle Post-Intelligencer (01-19-2006) that introduces some new tomatoes and other vegetables for 2006.

Seattle Tilth has an article by Kirsten DeLara (2011) called “Grow Great Tomatoes in Seattle” which includes a list of the author’s favorite varieties for our area. Also check Seattle Tilth’s annual list of tomatoes available at their sales, and their reports on tomato tasting results.

Mother Earth News published an article on the best Pacific Northwest varieties in February/March 2010.

propagating Schisandra fruit vine

How can I propagate the Schisandra fruit vine?

It does not sound like the easiest plant to propagate from seed. Cuttings or layering might be less challenging. The Maine Organic Farmers and Gardeners Association has a guide to growing Schisandra, including propagation information. Here is an excerpt:
“Propagate Schisandra by seed, cuttings or layering. The seeds can be planted in prepared seedbeds 1/4-inch deep in the fall soon after they ripen or indoors in March. Dry seeds need to be soaked overnight. In Herbal Emissaries: Bringing Chinese Herbs to the West, Steven Foster and Yue Chongxi say that in China an acid scarification process is sometimes used, because the seeds have such a hard coat.”

Plants for a Future’s database includes propagation details for Schisandra chinensis:
“Seed: best sown in the autumn in a cold frame. Pre-soak stored seed for 12 hours in warm water and sow in a greenhouse in the spring. Germination can be slow and erratic. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in light shade in the greenhouse for their first 2 years. Plant them out into their permanent positions in early summer.
“Cuttings of half-ripe wood, 5 – 8cm with a heel, August in a frame. Overwinter in the greenhouse and plant out in late spring.
“Layering of long shoots in the autumn.”