Elisabeth C. Miller Library

Gardening Answers Knowledgebase

Search for gardening questions with researched answers, plus gardening tips, book reviews and recommended websites.

Browse the Knowledgebase

 


Recently Added Questions

Question:

[Pistacia] cover

Can you tell me the botanical name of the tree that produces these oil-rich turquoise lentil-sized seeds? The trees grow in Amadiya, on a high plateau in Northern Iraq, near the border with Turkey. I grew up snacking on the seeds, and I know the Neo-Aramaic and Arabic name (butma or butum) for it, but not the scientific name.

Answer:

The tree is a species of Pistacia, most likely Pistacia atlantica ssp. (subspecies) kurdica. There are various English common names for the tree, including terebinth, Persian turpentine tree, and Mount Atlas mastic tree. There is a documented population of this subspecies of Pistacia growing in the town of Amadiya, Iraq. (It does well on steep, dry slopes in high elevations.) These trees are often found growing in association with oak and walnut trees. (This document uses the synonym, Pistacia eurycarpa).

According to Avinoam Danin’s Plant Stories on Flora of Israel Online, only female trees of this dioecious tree produce fruits which are red when young, turning turquoise once successfully pollinated. "When the thin skin is removed the thin but hard brownish stone is reached. When the seed is opened, its green food reservoir is seen. In color it resembles the seed inside the pistachio nut. […] The common name in Arabic for three of the species known in our area is 'butum.' This name has preserved the ancient Talmudic name 'botnim' or 'botnah.' The scientific name Pistacia is also a derivative of a vernacular name [used in Iran]." Danin mentions that the fruits are gathered in fall, dried, and sold in spice shops in Israel. They are also pulverized and used to flavor special sweet cakes.

The tree has a long history in the Middle East, where it can be traced back to the Hebrew bible, and to stone steles describing Mesopotamian gardens and palaces.

Some sources, such as this information from University of British Columbia Botanical Garden, say the fruit of Pistacia atlantica is not eaten "directly" (because it tastes of turpentine to some palates), but taste is subjective and varies in different cultures.

There are many medicinal and ethnobotanical uses of this plant’s fruit and resin.

Question:

Can you help me identify an insect that I see in the height of summer? It looks like a black and off-white moth or butterfly in flight, but when it lands, it looks like a dull beige- or gray-colored cricket.

Answer:

What you describe sounds like a road duster, also known as Carolina grasshopper (Dissosteira carolina). According to Merrill Peterson's Pacific Northwest Insects, it is often found on dusty or dirt roads and paths, sidewalks, and sandy beaches. It is not easily noticed until it flies, flashing its patterned hindwings. The hindwing pattern is unique to this species, though it somewhat resembles the Mourning Cloak butterfly. They are mostly active in the daytime, and seem to be generalists about food, eating grasses and forbs (herbaceous flowering plants) from what is available in their habitat.

This page from University of Wyoming has additional information about its food and migratory habits. A page on insects of eastern Washington mentions that birds, bats, praying mantis, and spiders eat Carolina grasshoppers.

Question:

Can I grow saffron in the Seattle area? I'd like to be able to use it in cooking, and save on the expense of buying it at the store.

Answer:

I wondered about this myself. A few years ago I bought a handful of Crocus sativus corms at the Hardy Plant Society of Washington's fall bulb sale, planted them in a dry corner of my sandy herb garden, and promptly forgot they were there. The following October those corms sent up lovely pale flowers with the characteristic deep red threads, which persist even as the petals begin to fade. That's when the gardener can swoop in, pluck the threads, and leave them to dry on a plate for a few hours. They shrink drastically as they dry, down from about four centimeters long to two, and the color deepens to the rusty red-orange familiar from those tiny spice jars. I'm happy to report that homegrown saffron is every bit as rare and subtle as the imported type, and my cluster of flowers seems to grow a little each year.

According to the book The Culinary Herbal by Susan Belsinger and Arthur O. Tucker (Timber Press, 2016), it's best to collect the flowers in the morning. Spread them out on a table and split each blossom down the stem. With your fingers, remove the three-part stigma (only this part of the plant is edible). Place the saffron stigmas onto a fine-meshed screen and dry over gentle heat, or in the oven with only the oven light on. The stigmas should feel dry when they are ready for use. Store in tightly sealed glass jars away from direct light, and away from humid conditions.

Pacific Northwest writer and gardening expert Mary Robson wrote an article entitled "A Mini Saffron Harvest" in the Seattle Times (September 4, 2002). Here are excerpts:
"The saffron crocus is botanically Crocus sativus (sativus is the old Latin for any plant used medicinally or for cooking). The crocus corm (the little unit you plant) resembles that of the spring-bloomers: it's firm, about the diameter of a thumbnail, and will often show the slightest white sprig on top where new shoots will emerge. But only the fall crocus yields the spice.
"Warning: When purchasing bulbs, don't get saffron crocus confused with a plant that also blooms in fall and is called 'autumn crocus,' Colchicum autumnale — which is poisonous in all its parts. […]
"To thrive here, it needs dry, sunny summer conditions and good winter drainage. One successful local grower used a raised bed facing south; these little crocus corms loathe wet feet. Soil doesn't need unusual amendments, it must simply drain well. Plant the corms in early September, about 4 inches deep, watering them in. The first year, a few deep lavender flowers will emerge in October, totally leafless.
"To produce saffron year after year, let the leaves emerge and grow. They come after the flowers, resemble grass, and slowly grow longer and longer through the winter until they can be 18-24 inches long in spring.
"They're floppy and funny looking during the spring when 'normal' crocus are putting out flowers. Keep the plants watered during leaf growth. (This is easy, because their leaf growth coincides with our wet season.) Allow them to die back naturally, which will be about April. Keep the saffron crocus hiding underground dry throughout the summer. The second year, bloom will be heavier."

Question:

I noticed a plant called Echibeckia for sale at a neighborhood grocery—must be some kind of cross between Echinacea and Rudbeckia. Why would plant breeders do this? Are these crosses garden-worthy? Will they be as attractive to pollinators as their parent plants?

Answer:

xEchibeckia is described as an intergeneric cross (the x represents a cross between two genera), but according to Plant Delights nursery owner Tony Avent (quoted in Greenhouse Grower, March 2015), it does not appear to differ from an ordinary Rudbeckia hirta. "'We have to be careful with intergeneric crosses and make sure they are truly what they say they are,' he says. 'If we don't, we will lose credibility with consumers, something our industry can’t afford.'"

In her book Butterfly Gardening (Princeton University Press, 2018), Jane Hurwitz mentions this very issue. This trademarked (i.e., propagation prohibited), human-made cross is said to have larger and longer-lasting flowers, faster growth, and disease resistance but it may be "less useful to butterflies and their caterpillars. […] Given the wide number of variables that altered plants introduce, it is easy to summarily dismiss garden plants that have been bred to differ from the straight species as harmful to the garden food web. However, these plants are a fact of life and are promoted by a large, thriving, retail nursery industry […] so the plant buyer should be aware of both their virtues and their shortcomings."

If you want to grow only those plants specifically known to attract pollinators and beneficial insects, then plant species Echinaceas and Rudbeckias, or choose cultivated varieties with a known track record in attracting them. But if you have fallen in love with this plant, why deny yourself the enjoyment of its presence in the garden? An informal survey of Pacific Northwest gardeners suggests that Echibeckia may do best in containers that are regularly watered and fertilized. Several gardeners found them to be short-lived (more like annuals than perennials), and susceptible to mildew at the end of a long season of blooming. Your experience may differ. Experimentation leads to discovery: it may do well for you, but if Echibeckia fails to thrive or attract as many pollinators as you might wish, there are always other plants to grow.

Question:

My "gas plant," Dictamnus albus, is finally flowering for the first summer ever, and I am starting to worry: can it spontaneously combust? It's planted close to the house. I remember stories from a couple of years ago about houses in Seattle catching fire because of sun or extreme heat igniting compost or soil in planters. Are there plants besides Dictamnus that are especially flammable?

Answer:

Dictamnus is not called the gas plant or the burning bush for nothing. It is in the same family as citrus plants, and contains extremely volatile oils that can indeed reach a high enough temperature to ignite. In Defense of Plants blog describes this aspect of the plant, and asks why a plant might have this capability (to burn out competing vegetation, or merely an unintended consequence of oil production). Excerpt:
"If air temperatures get high enough or if someone takes a match to this plant on a hot day, the oils covering its tissues will ignite in a flash. The oils burn off so quickly that it is of no consequence to the plant. It goes on growing like nothing ever happened."
Some gardeners amuse themselves and amaze their friends by demonstrating this flare of flame, but I highly recommend you not try it if your plant is up against your house!

You can read more about the flammable properties (and garden merit) of Dictamnus in the June 1995 issue of American Horticulturist. See the article "Ignite the Night" by Robert L. Geneve.

There are other flammable plants. Areas that are accustomed to preparing for summer fire season (such as Grants Pass, Oregon) have information about which plants are most (and also which are least) likely to ignite. The flammable list includes ornamental juniper, Leyland cypress, Italian cypress, rosemary, arborvitae, eucalyptus, and some ornamental grasses.

If you are concerned about the proximity of this plant to your house, you might consider transplanting it elsewhere in fall, though be aware that Dictamnus has a taproot and is not fond of being moved.