Growing Concerns: State blacklists butterfly bush as noxious weed

That old standard of country gardens, the butterfly bush, has been blacklisted by the Washington State Department of Agriculture. The State’s Noxious Weed Control Board classified Buddleia davidii, the most popular species of butterfly bush, as a Class C noxious weed.

Concern about the invasion of natural areas by the ornamental shrub led to the listing, according to Steve McGonigal, executive director of the State Noxious Weed Control Board. The state defines noxious weeds as non-native, invasive plants that are highly destructive, competitive or difficult to control, and, once established, threaten Washington’s natural resources and economy. That’s quite an indictment for that familiar, fragrant shrub beloved by butterflies and gardeners alike.

The Class C listing, which takes effect in 2005, won’t prohibit sales of butterfly bush, nor will we be required to yank it out. However, McGonigal encourages gardeners to cut off the flower clusters after they’ve bloomed and put them in the trash, rather than the compost bin. By deadheading and disposing of the spent flowers, gardeners can help stop the spread of wind-borne seeds. B. davidii, native to China, has been colonizing in wild areas and along roadsides, crowding out native plants that butterflies rely upon for survival. While butterflies are certainly attracted to B. davidii, their lives don’t depend upon it.

Washington isn’t the only place where butterfly bush is a problem. England and New Zealand, as well as several states on the Eastern seaboard, recognize B. davidii as an environmental threat. Oregon put it on its noxious weed list earlier this year.

To add insult to injury, and further confuse gardeners, botanists who classify plants have declared the spelling of the shrub’s botanical name is incorrect. Apparently, it should be Buddleja (yes, with a “j”), despite a couple of centuries with the original spelling. I choose not to change it until I’m commanded to do so by the Great Green Goddess of Gardening. The pronunciation hasn’t changed. It’s still pronounced BUD-lee-ah.

The shrub was named for Reverend Adam Buddle, the 17th century botanist who brought the first butterfly bush to England in 1774. In his honor, the plant was originally named “Globose Buddlebush.” I think I’ll stick to butterfly bush.

Gardeners can still enjoy the beauty of Buddleias without endangering the environment. The genus includes more than 100 species and cultivars. Most full-service nurseries will order them for you, if they don’t have them in stock. Another option is to send for them through the Internet. One site with less invasive butterfly bushes is www.butterflygardeners.com/buddleia.

If you’d like further information on the noxious weed control board, go to www.nwcb.wa.gov.

Amaryllis

won’t bloom?

Last week I received an e-mail from Leah Ann, who has an amaryllis that bloomed beautifully the first year. Since then it has sent up greenery and developed another bulb, but no flowers. She wants to know why this otherwise healthy plant doesn’t bloom.

First of all, Leah Ann, are you allowing the plant to go dormant in the fall? Like most plants that grow from bulbs, it needs a rest period or it won’t bloom. As I mentioned in my last column, put it in a cool room and stop watering and fertilizing. The foliage will yellow and you can then cut it back. Within a few weeks, the flower spike should appear. Return it to the windowsill and resume watering and feeding.

During the growing season, use a water-soluble houseplant fertilizer every second or third watering. I’ve used several well-known brands with good results, but some growers recommend an African violet fertilizer. Don’t give it any more than recommended on the label.

Amaryllis doesn’t mind being pot bound as long as it’s fed and watered, but if it’s bursting at the seams, carefully move it to a pot not much bigger than the bulb. Do this just as the flower stalk is beginning to develop, being careful not to disturb the roots. Use porous soil with some peat moss or Perlite added. Add a little compost, and to kick-start your slow bloomer, Leah Ann, try a teaspoonful of bone meal. Be sure to leave the top third of the bulb exposed.

I hope this helps, Leah Ann. If that reluctant amaryllis still won’t bloom, relegate it to the compost pile and buy another bulb, now that stores have a good variety in stock.

Mariana Graham writes this biweekly column as part of her volunteer efforts as an Island County Master Gardener. E-mail her at frogardn@whidbey.net.

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