Plant of the week: Hyacinth

Hyacinth. (Ginny Williams, Baltimore Sun / February 16, 2012)

My mother's landscape is full of pachysandra and periwinkle ground cover, both of which are on invasive species lists. Do I need to pull all of it out this spring?

These two are different from most non-native invasive plants. Yes, these popular groundcovers are invasive when they are planted adjacent to a natural or park area, where they'll expand indefinitely and crowd out native plants. However, in a typical yard, expansion can be controlled. And they do not produce berries that birds spread or seeds that blow or wash away. They can be valuable ground cover because their thick growth can be used to prevent erosion and weeds, resulting in less herbicide use. To keep them from invading your turf, edge beds with plastic, metal or masonry.

Annual National Invasive Species Awareness Week is coming up Feb. 26-March 3. Many invasive species enter the country in shipping containers, so with the bustling port of Baltimore, all Marylanders need to keep a sharp eye out for suspicious plants, weeds or pests, and report them by calling or emailing us. Attach a digital photo if you can. We can determine whether you've spotted something new. Invasive species often build up populations for several years before they're discovered. We'd be smart to catch them before their population explodes.

Do houseplants really improve the air in your house, or is that an old wives' tale?

Sometimes those "old wives" knew what they were talking about. Houseplants take carbon dioxide out of the air and emit oxygen we need, just as all green plants do. But their benefits don't stop there — they can also filter out contaminating chemicals such as formaldehyde, benzene and tricholoethylene. NASA extensively studied which plants make the best air filters. Although it was interested in plants for space stations, its list of the best-filtering houseplants is available to all online at http://en.wikipedia.org/wiki/List_of_air-filtering_plants.

University of Maryland Extension's Home and Garden Information Center offers free gardening and pest information. Call 800-342-2507 or send a question to the website at hgic.umd.edu.



Plant of the week



Common, Dutch or garden hyacinth



Hyacinthus orientalis

Beautiful and fragrant harbingers of spring, hyacinths emerge from bulbs that are in the asparagus family. The most popular shades are violet, pink and white. Whether planted in rows, clusters and containers, or naturalized throughout a landscape, be sure to place them where you'll encounter the heavenly scent. Give them sun or light shade with fast-draining, organically enriched soil, and water generously during the growth and blooming period. For maximum enjoyment as cut flowers, cut when about half of the buds have opened. One admonition: Hyacinths contain oxalic acid. Persons with sensitive skin should handle them with gloves to avoid skin irritation.

—Lew Shell