growing and caring for Cornelian cherry trees

Can you tell me how to grow Cornelian cherry? Do I need more than one tree to get fruit? Also, what kind of soil and fertilizer does it need?

Cornelian cherry, or Cornus mas, is not especially fussy about type of soil, but prefers well-drained moist soil that is somewhat rich. According to Lee Reich’s Landscaping with Fruit (Storey, 2009), the tree is at least partly self-fruitful, but planting a second tree (a different cultivar or clone) will increase fruit yield. I don’t think there are particular fertilizer needs for this tree, but you can provide a mulch of compost in spring or fall if you wish. Reich says to “plant this tree carefully, keep weeds at bay at least for the first few seasons, water as needed during the first season and you’ll have little else to do for your tree beyond enjoying looking at it and harvesting the fruits.”

The local website of Great Plant Picks has information about this tree.

Washington State University at Mount Vernon’s fruit research center offers a list of cultivars tested in 2007:
Cornus mas

“Elegant”
“Olga”
“Pioneer”
“Red Star”
“Sevetok”
“Yevgenii”

sourcing non-GMO seeds

I read an article recently that said some of my favorite seed companies are now owned by Monsanto. I don’t want to use genetically modified seeds in my home garden, so I’d like to know where I can find more information on the sources seed companies use for the seed I am buying.

You may be referring to the January 2009 issue of the PCC Newsletter regarding Monsanto purchasing many of your favorite garden and farm seed catalogs. Territorial Seeds, Johnny’s Seeds, Park Seed, Burpee, Cook’s Garden, Spring Hill Nurseries, Flower of the Month Club, and Audubon Workshop are not owned by Monsanto or Seminis. PCC subsequently posted a retraction.

The folks at Organic Seed Alliance are a great resource on this issue. Here is what they suggest:
“For gardeners interested in buying non-GMO seeds, the best bet is to purchase seeds from seed companies who sell only organic seeds and who have signed the Safe Seed Pledge.”

For further reading on the subject, see this February 2005 article (now archived) by Matthew Dillon from the Rodale Institute on Monsanto’s purchase of Seminis. Environmental News Network also has information about a September 2008 discussion forum with writer Michael Pollan and Monsanto CEO Hugh Grant.

encouraging Christmas cactus to bloom

I have a Christmas cactus that is very healthy and blossomed profusely last November. I attempted to duplicate the same environment that the cactus had a year ago, but that wasn’t possible, and it didn’t produce a single blossom. The foliage is glossy with health, but I don’t water the plant for a couple of months in the fall to stress it a bit to encourage blossoms.

I put the cactus in our dark, cool garage for the month of October just as I did last year. When I returned the cactus back upstairs in our house to its usual south window spot and watered it, it gave no blossoms this year. Why?

I’ve looked online and in books for info on encouraging bloom, but I haven’t come across much about Christmas cactus. The cactus gets direct southern light all year except for the month when it is in the garage, which has only a north window. Is lighting the problem? The garage is about 65 degrees F, same as last year, so I’m thinking the temperature isn’t part of the problem, or is it?

There may be a combination of factors involved in the lack of flowers on your plant. If it is a young plant, it may have needed repotting. It may not have been in the dark, cool environment quite long enough or soon enough. According to The Complete Houseplant Survival Manual by Barbara Pleasant (Storey Publishing, 2005), the ideal conditions for Christmas cactus (Schlumbergera hybrids) are as follows:

Bright light from late spring to fall, and moderate light from late winter to early spring
65 to 80 degrees from late spring to late summer, and 50 to 65 degrees during fall and winter
Balanced fertilizer every 2 weeks from spring through summer, and monthly in fall and winter
From spring through fall, keep soil lightly moist but in winter, it should nearly dry out before watering sparingly
Repot young plants each summer; older plants can be repotted every 2 to 3 years
Plants tend to have a lifespan of 5 to 6 years, but you can propagate them from stem cuttings

Clemson University Extension has additional information on growing Schlumbergera. Here is an excerpt:
“The secret of good flower production involves temperature and dark (photoperiod) control. To flower, plants need bright light; night temperatures between 55-65; long nights–13 hours or more of continuous darkness each day is required before flowering will occur. Long nights should be started about the middle of September and continued for 8 weeks.”

on the origin of common plant names

Can you recommend a book that talks about the origins of the common names of plants, not just their botanical Latin equivalents?

The best book I have found is Geoffrey Grigson’s A Dictionary of English Plant Names, published by Allen Lane in 1974. It goes into a great deal of detail, and usually provides the approximate date when the name came into use. Another good resource is Flowers and Plants: An International Lexicon with Biographical Notes, by Robert Shosteck (Quadrangle, 1974).

growing pomegranate trees as a fruit crop in the PNW

I live in Enumclaw, WA which is USDA hardiness zone 8a, and am hoping to grow pomegranate trees as a fruit crop. Can they be grown here or would they need the aid of a greenhouse?

Most of the Pacific Northwest nursery sources for pomegranates (Punica granatum) say that their varieties are hardy in zones 8 through 10. That being said, they may survive our conditions, but they might not have sufficient flowers and fruit set if you are trying to grow them as a crop outdoors. For basic cultural information, see the following, from California Rare Fruit Growers:
“Pomegranates prefer a semi-arid mild-temperate to subtropical climate and are naturally adapted to regions with cool winters and hot summers. A humid climate adversely affects the formation of fruit. The tree can be severely injured by temperatures below 12 degrees F. In the U.S. pomegranates can be grown outside as far north as southern Utah and Washington, D.C. but seldom set fruit in these areas. The tree adapts well to container culture and will sometimes fruit in a greenhouse.”

Purdue University has additional information about growing pomegranate.

According to Trees and Shrubs for Pacific Northwest Gardens by John Grant (Timber Press, 1990), pomegranates need the warmest possible site in our area to flower well (such as near a south- or west-facing wall), and are unlikely to develop ripe fruit.
If you want to grow them for fruit rather than their ornamental qualities, you may need a greenhouse setting. There are some varieties which are more likely to succeed in the Pacific Northwest than others. Check out the selection at Raintree Nursery in Morton, WA and One Green World in Molalla, OR.

getting more fruit from a quince bush

We have a quince bush and we’d like to make quince jelly, but the fruit this year was very small and seedy. We made some jelly, but with the seeds mixed in, since there wasn’t much fruit outside the seed part. Last year, I think we had more quinces and they were larger. We also have a very old pear and an apple tree, and they both had less fruit this year too.

Is there anything I can do to get more fruit from the quince bush? Should it be cut more? Or less? More water? Fertilizer?

Is your quince bush the ornamental quince, botanical name Chaenomeles, or the edible quince, Cydonia oblonga? The fruit of ornamental quince is edible, but tends to be less known for its flavor than that of Cydonia oblonga. To help you determine which quince you are growing, take a look at the following information.

A local gardener’s website, Paghat’s Garden, describes ornamental quince and the use of this plant’s fruit:
“Having been developed for the pre-spring and early spring flowers, not all these shrubs fruit well. But there are also a few cultivars developed in northern Europe with fruit production in mind. Generally the market-variety quinces are trees of a different genus altogether, namely Cydonia oblonga. But species of Chaenomeles were formerly categorized as Cydonia, and their tart fruits are also edible.”
Plants for a Future Database also describes ornamental quince.

There is an essay on edible quince (Cydonia oblonga) by Joseph Postman in Arnoldia (Harvard Arboretum publication), vol. 7 no. 1, which includes some cultural information. The amount of fruit production may vary depending on weather and other environmental conditions.

There are also discussions on the difference between the edible and ornamental quinces and their fruit, such as this one from University of British Columbia Botanical Garden, excerpted here:
“The big fuzzy fruit are the real quinces (Cydonia) and is the only member of its genus. The flowering quinces (eg., Chaenomeles) were once classified with the Cydonia quince trees. I think some Chaenomeles were called ‘Japonica’, but the ‘flowering quince’ name seems the norm now. Unfortunately the abundance of chaenomeles, and use of the name ‘quince’ for the Chaeonomeles contributes to the under appreciation of quince tree and its fruit.”
Another excerpt, from a nursery source:
“Like apricot and peach pits, European quince seeds contain cyanide… Most people know that they must never cook apricot or peach pits when making jam or jelly, but most do not know that this also applies to true quince seed.
Although often called Flowering Quince, Chaenomeles japonica is a very different plant, and it is these fruit that most North Americans are familiar with, although the flavour of the fruit is nowhere near as rich and aromatic as that of the true quince. The seeds of the flowering quince are not particularly dangerous, and may be cooked with the fruit, but I still would not recommend doing so.”

Cornell University also discusses the difference:
“Don’t confuse these quinces with several other quince-like species grown for ornamental purposes. There are many varieties of Japanese quince (Chaenomeles japonica) and common flowering quince (C. speciosa, C. lagenaria), attractive shrubs bearing showy pink, red or orange flowers in early spring.

Most of these ornamentals produce fruits that are hard and nearly inedible, though they have a high pectin content and are occasionally mixed with other fruits in jellies and preserves.”

Sometimes, weather conditions conspire to create a smaller yield of fruit in a given year. You might have had fewer bees and other pollinators. There could have been rain or cold weather and frost at the same time that the plant was in flower, and this could have disrupted pollination. Other factors might be a change in the amount of sun exposure, or an excess of nitrogen-heavy fertilizer which will result in lots of leafy growth and few flowers and fruit.

on the invasiveness of Bear’s breeches

I am wondering how invasive bear’s breeches is? I have heard it can be invasive in the Northwest. Will I be battling roots or suckers constantly? Can it take over any plants near it?

Acanthus mollis, or Bear’s breeches, is not listed as noxious in King County, Washington State, or on the federal list of noxious plants. This is not the same as saying it isn’t potentially aggressive, although I’ve never heard about it being a serious problem here. It is considered invasive in parts of Australia, though.

The Plants for a Future database offers the following information on this plant and its growing habits:
“Plants can become invasive, spreading by suckers, and they are difficult to eradicate due to their deep roots.”

According to the Pacific Northwest site, Rainyside Gardeners, it is sometimes difficult to get this plant to bloom. A Washington State University Extension site says that Acanthus mollis is potentially invasive in climates warmer than ours.
“This species is classified as a groundcover in that any pieces of root cut from the original plant can easily contribute to further plant spread.”

If you want to grow it but are concerned about it spreading, you could try containing the roots with an 8-inch root barrier (similar to what is used to keep running bamboo in check). On the other hand, if you have this plant and decide that you wish to be rid of it, the book Wildly Successful Plants: Northern California Gardens by Pam Peirce and David Goldberg (Sasquatch Books, 2004) says that removing every bit of root over two or three seasons of growth should get rid of the plant. If you cannot eradicate it by continually digging up each new shoot, you may have some luck using a flame weeder (with due caution and appropriate protection). Northwest Center for Alternatives to Pesticides describes how to use this tool.

encouraging daylilies to bloom

How can I get my Stella d’Oro daylily to rebloom? It had a huge show the first 2 weeks of July, now it has stopped.

It has become a large plant. I probably should divide it. When should that be done?

Does it like or need fertilizer? I think it got run-off fertilizer from the roses, and that may be why it is such a large plant.

According to Stefan Buczacki’s The Plant Care Manual (Crown, 1993), you should remove individual flowers as they fade, and cut down flower stems with nothing but fading flowers left. This plant should be divided after three years (do this in fall or spring). This may help with flowering, as overcrowded clumps flower less profusely. Hemerocallis should be mulched in spring and early fall, and you can feed with bulb fertilizer or bone meal in early spring.

Here is a useful link to a factsheet on care for daylilies, from Clemson University.

last frost dates

This year is my first in a house with a yard. I’m very
excited to try my hand at growing some food this year. Many of my seed packets say to plant after the last frost or when the soil reaches certain temperatures. Having never planted anything at the beginning of a season before, I
have no idea when any of these temperatures happen around here! Can someone give me some temperatures and approximate times when they are normally reached?

The last frost date in Seattle can be as early as
March 22, but to be on the safe side, April 15-20 would be more
definitive. This information(now archived) can also be found on the web site of local
gardening expert, Ed Hume. The web site also provides further details. Excerpt:
“The last frost date for an area is the last day in the spring that you could have a frost. The average last frost day is the date on which in half of the previous years the last frost had already occurred (so about half of the time it will not frost again and it will be safe to plant tender plants). Most planting directions are based on the average last frost date. The calendar based directions I give (Now it is time to… etc.) are usually based on an average last frost date of April 1st.

An important thing to realize about last frost dates is that the actual date of the last frost is different every year. It can be much earlier than the average or much later. This is especially important for tender plants that can be killed by a frost. For hardier plants, the average last frost date is more an indicator of general growing conditions than a danger sign.”

The closer to the water the garden is, the milder the temperatures.
The moderating effect of Puget Sound or Lake Washington, for instance,
which results in milder winter temperatures, extends inland for some
distance. If your garden is more than a mile or so from water, that
moderating influence could vary. The last frost date for Vashon Island is
April 5; for the Sea-Tac area, April 9. Again, add at least a week and
check your own garden temperatures and patterns.

on Iris sibirica ‘Mantra’ and its cultural requirements

I am looking for information on a Iris sibirica ‘Mantra.’ I want to know what it looks like, what its cultural requirements are etc. If you can find an image, that would be awesome.

The iris you mention is actually not a Siberian iris. Here is a photo from the Miller Garden website’s alpine collection which lists this as a Pacific Coast iris, rather than Iris sibirica.
This iris won an award of merit from the Pacific Coast Iris Society in 2000. Here is general cultural information from the King County Iris Society.

Pacific Coast Native Iris (PCN), or Californicae (CA), are much sought after in the Pacific Northwest as our climatic conditions are ideal for them. Their graceful and dainty flowers bloom April to June on stems 1′ to 2′ tall, in a wide variety of striking colors and patterns. These irises thrive in the marine coastal climate, with dry summers and cool, wet winters. Plants are very prolific and grow readily from seed. Transplanting, however, can be difficult. They are best moved or divided in the early fall, when root growth is active and can continue well into winter. Plants can also be moved prior to spring bloom.

Transplants must be kept well-watered until natural rainfall can maintain high soil moisture. They should be heavily mulched with bark dust, pine needles or leaves, to prevent frost damage to newly developing roots. Once established, plants are usually tolerant of normal freezes and periods of drought. If frost damage occurs to leaves, wait until well into spring to watch for signs of new growth. PCNs should receive at least a half a day of sunshine.