Home Garden: You’re Not Welcome Here How to

“You’re Not Welcome Here”

RIDDING THE GARDEN OF INVASIVE SPECIES

By Janice F. Booth

With a new year before us, you may be organizing, clearing out the detritus that collects in closets, desk drawers, and cupboards. Let me suggest that while you’re in this frame of mind, it’s a good time to plan for some spring cleaning of unwanted and unnecessary stealthy invaders of your garden.

Look over your garden notes, your photos, and memories of last year’s garden. Where were the trouble spots? What got out-of-hand? Let me review with you some of the unwelcome or troublesome invasive plants that you’ll want to keep an eye on or eliminate all-together if they show up in your garden.

Here’s a review of the characteristics, the types, and the most familiar of these sneaky invaders.

Characteristics

Invasive plants can damage, even eliminate the healthy growth of other plants in your garden. Here’s how to identify them:

Types

Maryland’s Department of Natural Resources (DNR) has come up with a WANTED List. You can print out your copy at Dnr. maryland.gov/wildlife/documents/invasive-plants.

The DNR identifies two designations of invasive plants:

TIER ONE: These are plants which may not be sold and should be eradicated. (Bamboo and amur honeysuckle are examples). TIER TWO: Plants that may be sold but only with clear warnings to the buyers. They’re likely to grow out of control at the first opportunity. (Japanese wisteria and Scotch broom are examples).

Rapid growth and maturation Prolific seed production Successful seed dispersal, germination, and colonization. (I know; this sounds like something out of a low-budget Sci-Fi movie.) Rampant vegetative spread. (That’s right; they are hardy plants and eager to spreadout in your flowerbeds… and beyond!) Out-compete native plants, syphoning off the moisture, nutrients, and sunlight from nearby plants.

This troublesome vegetation sneaks into your garden as seed, root, runner, or rhizome (sturdy stems that travel just below the surface, from which new shoots spring up) and proceeds to have its way with your garden.

Familiar invaders

The DNR identifies familiar plants that we often see here in Maryland in open meadows, along stream banks, and even—dare I say it—in our own gardens. If you’re harboring some of these in your garden…BEWARE. Note: invasive plants have evolved to survive, no matter what. One sneaky adaptation they have is to start slow, and over time pick up speed! For example, you may have a lovely clump of silver grass along a path for years, and then, one spring you look in amazement as that pretty clump emerges as a huge, indestructible mound of silver grass.

BAMBOO: great for privacy and fishing poles, but its rhizomes (sneaky horizontal roots) travel everywhere, and bamboo shoots will pop up from the rhizomes anywhere they please! Once they emerge, the new plants will send out their own rhizomes, and the bamboo becomes very difficult to control or eradicate.

GARLIC MUSTARD: this plant is toxic to butterfly larvae. Its delicate-looking leaves and tiny white flowers harbor roots that change the soil’s chemistry, making it inhospitable for other plants for years and even permanently.

CHINESE SILVER GRASS: as I mentioned previously, this plant is seductive; it wants to be admired with its slender leaves striped in pink and silver and its graceful, feathered stalks that bend and nod in the breeze. Before too long, its root mound will grow like the Blob in that sci-fi movie.

FIG BUTTERCUP OR LESSER CELANDINE: these shiny, heart-shaped leaves and bright yellow flowers might show up along your stream bank or boggy area. They’re sweet, pretty plants, but their roots mat, and before long they choke out surrounding vegetation.

PALE YELLOW IRIS: you may have these delicate-looking iris in or near your pond. Beware: as you may already have learned, their sap can be irritating to your skin. (So, wear long gloves if you pull them out.) In addition, they’ll sicken any animal that tries to eat them.

AUTUMN OLIVE: this sneaky shrub can be any size and produces pretty, creamy-yellow flowers from February to June. (Tempting, I know, for those early months in the garden.) And the Autumn Olive gets its name for its pretty, red berries in fall. But, if you try thinning out the plants, you find there are thorns along the branches. It does not want to be disturbed!

JAPANESE BARBERRY: this shrub’s thorny branches are a delicacy for birds, believe it or not. Birds eat this barberry’s late-summer, red berries and its thorns. The barberry’s small leaves turn purple in the fall, making them a tempting addition to gardens. But, beware. They’ll take over.

BRADFORD PEARS: yes, I know, at one time the State planted them along roadways. They’re noted for their profuse, white spring blossoms and red leaves in the fall. But these soft-wood trees propagate seemingly by magic and will appear anywhere they like.

There are other, equally enticing and sneaky plants that may win your heart at first, but give you nightmares over time. If they’re pretty and they seem to grow effortlessly, there’s probably a reason. Invasive plants have evolved and adapted to stay alive in the garden or wild, with or without your permission.