Skip to content
Elisabeth C. Miller Library

Archives: Plant Answer Line Q & A

Plant Answer Line questions and answers.

Attracting hummingbirds

What do hummingbirds eat? I want to attract them to my yard.

 

According to the Hummingbird Society, hummingbirds primarily eat nectar from flowers. They also eat small insects and spiders as sources of protein. For more information on their needs, see the website of the Hummingbird Society.

The City of Bellingham has a helpful guide to attracting hummingbirds which includes a list of plants which are nectar sources. Rainyside Gardeners also has a list of nectar plants for hummingbirds in the Pacific Northwest. Oregon State University Extension’s “Attract Hummingbirds to Your Garden” by J. Olson and N. Allen (follow link “for more information” at the end of the article) is also a good starting point.

The Miller Library has many books about creating a hummingbird garden, including a book published by the Brooklyn Botanic Garden that provides lists and descriptions of plants that attract hummingbirds, arranged by geographic region (Hummingbird Gardens, 2000, edited by Stephen W. Kress).

,

Growing hawthorn in the Pacific Northwest

Hawthorn fruit is valued in traditional Chinese medicine for digestion, circulation, blood pressure, and anything to do with the heart. What types of hawthorn could I grow here in the Pacific Northwest that share the same medicinal properties as the ones used in China? I found some fruit on a tree in my neighborhood that reminds me of the dried hawthorn fruit we used, but someone told me this was a strawberry tree, not a hawthorn.

 

Strawberry tree is the common name for Arbutus unedo. Its very bumpy fruit is edible but not especially tasty (the species name means ‘I eat one,’ because one would be enough to convince the eater to seek a better food source!). Unlike deciduous hawthorns, Arbutus is evergreen. I can imagine, if you have only seen medicinal hawthorn fruit in dried form, it would be easy to mistake it for the strawberry tree’s fruit. Chinese hawthorn fruit has a comparatively smooth surface, though it is dotted with lenticels (that allow for exchange of gases between the outside world and the fruit’s interior).

We are not medical professionals, so we cannot address the medicinal benefits of any plant. However, there are several species of Crataegus (hawthorn) that are native to China, and some of these have fruit considered useful for the medicinal purposes you mention. The species that come up most often are Crataegus pinnatifida (shan zha) and Crataegus hupehensis. In the article “Hawthorn (Crataegus) Resources in China” (Taijun Guo and Peijuan Jiao, HortScience, Vol. 30(6), October 1995), there is a list of all the species that grow in various regions of China. The most useful ones are likely those that have sizeable fruit. There are also quite a few cultivated varieties, especially of C. pinnatifida, C. scabrifolia, and C. hupehensis. There is some history of hawthorn’s medicinal use in Europe as well, but with different species (mainly Crataegus monogyna–an unregulated noxious weed in King County– and Crataegus laevigata, previously called C. oxyacantha).

If you search online nursery inventory for the Chinese hawthorn species mentioned above, you will see that a cultivar of Crataegus pinnatifida called ‘Red Sun’ is available from Raintree Nursery in Washington, and One Green World in Oregon. You could certainly try growing it here, provided you have the right space for a 15-foot tree that needs full sun. When the fruits ripen (in the fall here), you could even scoop out the seeds, fill them with red bean paste, skewer them, and dip them in sugar syrup to make tanghulu, a treat for Chinese New Year.

, , ,

Sahlab and other edible orchids

When I lived in the Middle East, there was a warm drink we enjoyed called sahlab (spelled with variations in different countries, such as salep in Turkey) that is made from dried powdered orchid roots and milk. It can be sweetened, flavored with rosewater and sprinkled with cinnamon and finely chopped pistachios. The powder made from the roots was ubiquitous in markets in my country, but is hard to find here. I don’t know which kinds of orchids are used traditionally. Do all orchids have tubers that are edible (or drinkable)? Are there Pacific Northwest native orchids that could substitute for the wild orchids used in Middle Eastern sahlab?

 

The use of orchid tubers, whose stored starches are nourishing both to the orchid plant and to humans, goes back many centuries, and over time, sahlab/salep in one form or another migrated across Europe. In the Middle East, people typically use tubers from wild native orchids. In Israel, the family Orchidaceae is referred to as Sahlavim [plural], and the genus Orchis is called Sahlav. In Greece and Turkey, the drink is often made from the tubers of Orchis mascula, Orchis militaris and Anacamptis morio. Other sources include Dactylorhiza and Ophrys species. By the 18th century England, salep or ‘saloop’ was made from Orchis mascula, and was sold by street vendors as a lower cost alternative to tea and coffee. It also went by the name ‘dogstones’ because of the tubers’ resemblance to testicles. In his 1640 book Theatrum Botanicum, John Parkinson lamented that “our pharmacists are wont to adjudge every sort of orchid root an aphrodisiac,” possibly a throwback to the notion that a plant’s appearance indicates its medicinal uses (the Doctrine of Signatures).

An important consideration is the conservation status of some orchids, including species which have been harvested for making sahlab. CITES, the Convention on International Trade in Endangered Species of Wild Fauna and Flora, restricts importing all orchids, because of the difficulty in distinguishing one from another, especially by looking at tubers alone. This may account for the scarcity of sahlab powder.

Many orchids have edible properties–just think of vanilla, made from the pods of Vanilla planifolia. It is hard to say which locally native orchids have tubers best suited to making sahlab, and harvesting wild orchids is problematic from a conservation standpoint. For clues about edible uses of orchids in this country, I
searched the Native American Ethnobotany Database. Numerous tribes (including some in the Pacific Northwest) have used a wide variety of orchid species for edible, medicinal, and spiritual purposes. Those which grow here include: Corallorhiza maculata, Goodyera oblongifolia, Platanthera dilatata, Platanthera stricta, and Spiranthes species. Goodyera, for example, is mentioned in Erna Gunther’s Ethnobotany of Western Washington as a tonic among the Cowlitz.

Rather than try to find or grow and harvest orchids to make your own sahlab, the best thing would be to look for prepared sahlab powder that is made from sustainable sources.
Excerpt: “Salep can be produced sustainably, and the species of orchids that yield the best salep (Orchis mascula, Orchis militaris and Anacamptis morio) can be cultivated. Local propagation and sustainable cultivation alleviate harvesting pressure on wild orchids but subsequent trade poses challenges in the context of national and international legislation, such as CITES.”

,

Propagating Primulas

I have some Primulas I would like to propagate, specifically Primula elatior and Primula veris. What is the best method, and when is the best time?

 

The timing will depend on the propagation method you choose. The American Horticultural Society’s Plant Propagation (edited by Alan Toogood; DK Publishing, 1999)says that division is done in early spring or after flowering; however, this method is not recommended for any species except Primula vulgaris and Polyanthus primroses. Although division is a healthy practice for some species, it can weaken others.

You can raise your primroses from seed, which has the benefit of being a virus-free propagation method. This is done in either mid-spring or in late summer to fall(the later time period is rated as easier than the earlier). However, Primula elatior, Primula veris, Primula vulgaris, and candelabra-type primroses may hybridize if you do not isolate them. Depending on your outlook, this could be a problem or an opportunity. The seeds are best sown when fresh, in a well-drained, moist soil mix rich in organic content.

There is some propagation information in this Alaska Master Gardeners article by Mary Jo Burns, entitled Growing Primula in South-Central Alaska. You may want to see if your area has a chapter of the American Primrose Society. Members of the Society have access to informative articles about all aspects of primrose cultivation.

,

Fig stump removal

I have a fig tree cut down to just above the ground and want to know how to stop it from
growing, i.e. putting up suckers. I plan to pave over that area and am afraid, because of its vigorous growth, that it will find a way up and out.

 

I recommend renting a stump grinder, or hiring a tree service to grind
the stump and the larger roots. You can water the area well to soften the
soil, and try digging up the remaining roots. You could try applying
full-strength vinegar to kill any shoots, or you can wait and continue to
cut them off as soon as they emerge. Over time, this should weaken any
part of the tree that remains in the ground, and it will eventually die.
You could also cover the area with black plastic once the stump and major
roots have been removed. This should suppress any growth coming up from
what is left of the roots. There are also chemical treatments which
should only be used with extreme caution, and exactly according to
directions on the product.

If you look at page 4 of this document on controlling invasive species from the Hawaiian Ecosystems at Risk project, you will see the different approaches used to remove fig trees and their roots from a natural area (in Central California), including physical and chemical methods.

,

Deadheading Clematis

I have a beautiful clematis in full bloom right now. Do I need to
dead head the spent blooms to make it bloom again? It is Clematis
‘Candida.’

 

In researching this question, I used Raymond Evison’s
excellent 1998 book, The Gardener’s Guide to Growing Clematis. Your
Clematis lanuginosa ‘Candida’ is considered a mid-season, large-flowered
type, and it often reblooms, according to Evison. In the chapter on
cultivation, he says, “Some clematis growers prefer to remove spent
flowerheads to encourage further crops of flowers, especially with the
early large-flowered single, double, and semi-double clematis. Certainly,
if the old flowers are removed with a length of stem with 2-3 nodes, new
growth will appear and a further crop of flowers will be produced. When
this is done, it is important to keep the clematis well watered and fed.
The only drawback…is that the attractive seedheads on this group of
clematis will be lost. A compromise can be achieved by removing only 50
per cent of the spent flowerheads…”

Northwest native indoor plants

I’ve taken up planning plants for our office, and wondered if
you could give advice. I’m looking for Northwest native plants that would be
happy indoors, in an office environment. Available sunlight will vary by
spot but is generally low (but I can probably swing some plant lights); air
is standard low-humidity commercial-building air.

 

Most Northwest native plants I can think of are not ideal for growing
indoors. However, I asked my colleague who used to garden for the Seattle
Public Library, and she says that the library is growing native species
of ferns indoors. She notes that they are especially prone to pests
(whitefly) and diseases (scale), and must be watered every day.

Below is the list of plants being grown in the main (Central) library
branch:

  • Acorus
  • Blechnum spicant
  • Adiantum pedatum
  • Carex elata ‘Bowles Golden'(tall)
  • other fern (Rumohra adiantiformis?)

I hope this helps. If you wish to reconsider using natives in favor of
more traditional choices for indoor plants, there are many more choices
available. Below are a few links that may be use to you:

Low Light Houseplants from University of Vermont Extension

Growing Indoor Plants with Success from University of Georgia Cooperative Extension

Interior Plants: Selection and Care from University of Arizona Cooperative Extension

, , , ,

Is it a crocus?

I just discovered a flower growing in my garden this fall. It looks very much like a large pink crocus. Someone told me it is called naked ladies. Is it actually a crocus? Is it poisonous?

 

Here is the tricky thing about common names: they often refer to more than one plant. Based on your description of a low-growing flower like a crocus, it sounds like Colchicum autumnale is growing in your garden. If it had long bare stems and lily-like flowers, you would be looking at naked ladies of another sort, that is, Amaryllis belladonna, or possibly a species of Lycoris (both of which are in the Amaryllis family). What they all share is the characteristic of flowering once the foliage has died back (hence the nakedness of a flower without leaves).

Colchicum is in the family Colchicaceae. It has a history of being misidentified as Crocus sativus, the source of saffron, which also flowers in fall. Crocuses belong to a different family, the Iridaceae. Mistaking Colchicum (also called meadow saffron, which adds to the confusion) with Crocus sativus (whose dried orange stigmas have culinary and medicinal uses) can have dire consequences. When the 17th century herbalist Nicholas Culpeper cautioned that “some have fallen into an immoderate convulsive laughter which ended in death” from consuming saffron, it is likely that people had ingested Colchicum stigmas, not saffron from crocuses. Colchicine (which is sometimes used as a gout medication) is highly toxic when ingested. Amaryllis belladonna and Lycoris are also toxic, especially to cats and dogs, but humans should not ingest any part of these plants, either.

Naked ladies were once naked boys, the prevailing common name before Victorian morality intervened and thought it too suggestive. Why ‘naked ladies’ is any less so is a mystery. It is not known who coined the name ‘naked boys,’ but an early flora of Nottingham by George Charles Deering (an 18th century German-born botanist and physician) documents their presence in the autumn garden. The name is thought to go back as far as the 16th century.

, , , ,

Paterson’s curse

What can you tell me about Paterson’s curse? It’s a weedy plant with blue flowers mentioned in an Australian novel about an Aboriginal community and their ongoing struggle with the effects of colonization.

 

Paterson’s curse is a common name for Echium plantagineum, also known as Salvation Jane, purple viper’s bugloss, Lady Campbell weed, blueweed, and Riverina bluebell. It is invasive in Australia, where it has overtaken pasture land. It is toxic to horses and other grazing livestock. (There is a similar plant, Echium vulgare, which is invasive in Washington State.)

The source of the name is said to come from the Patterson family (the plant dropped the second T through common usage over time) who introduced it to their garden in Cumberoona, New South Wales around 1880. However, according to Australian author Roger Spencer, the plant’s presence was first recorded in Australia in 1843, in the garden of John Macarthur, near Sydney. It began appearing in nursery catalogues by 1845, and by 1890 it was entrenched in New South Wales and South Australia.

There are two theories about the name Salvation Jane. In times of drought, when native pasture plants died back, Echium plantagineum was seen as a ‘salvation’ because it grew when nothing else would. The hooded shape of the flowers call to mind the bonnets of 19th century Salvation Army missionaries.

You might be interested in reading more about indigenous Australian uses of plants that predate colonization.

, , ,

Pruning Hellebores

I am noticing that the flower bud shoots for my hellebores (Helleborus x hybridus), are starting to push up above the soil surface. There is still a substantial stand of foliage in good condition.

My question is about pruning. I know I’ll need to prune about half the leaves away (I understand that the cut should be made at the base) to give the flowers more visibility. Does it harm the plant to prune it during this cold snap? Does it harm the plant to cut ALL the old leaves off in December as the bud stalks begin to appear?

I would appreciate any guidance you can give me, such as when and how extensively to prune them.

 

According to Hellebores: a Comprehensive Guide by C. Colston Burrell and Judith Knott Tyler, “all the hybrids maintain their foliage (…) throughout all or part of the winter (…) In any case, as the flower buds begin to stir in the center of the rosettes, it’s best to remove all the foliage to make way for the flowers. Nothing spoils the garden display like a tangle of flowers wrestling with winter-burned leaves. The juice is caustic and sometimes causes a rash, so take care when removing the old leaves.”

In The Gardener’s Guide to Growing Hellebores, Graham Rice and Elizabeth Strangman advise a more time-intensive method:
“The best approach is to cut off some leaves during the autumn and early winter when the garden is put to bed, concentrating on removing dead leaves and any showing signs of blackening (…) By Christmas time they should be thinned out sufficiently to leave a good circle. However, as our winters become windier it may be wise to remove them entirely at this stage. (…)Thin the leaves further as the flower stems emerge, then just before they are in full flower remove all the old leaves. (…) To compensate for the removal of the last of the leaves the plants deserve a good mulch.” They go on to suggest compost or a mulch of leaves for this purpose. The cold snap is unlikely to harm even recently pruned hellebores, as they seem to thrive in the cold.

, ,