Invasive plants in Maryland

By Phil Ourisson

I recently attended part of a webinar on invasive plants.  I decided to share some of the things that I learned.

We have several laws in Maryland regulating what can and cannot be done with invasive plants.  A number of the restrictions apply to the sale of some plants.  In particular, we know that a number of plants that Cape Conservation Corps tries to control in the Cape are still sold to nurseries, and recommended by landscapers. 

However, here is a list of the plants that are not allowed to be propagated, imported, transferred, sold, purchased, transported, or introduced, in Maryland:

Some other plants , while allowed to be sold, must be labeled with a sign that states (see image above) that it is an invasive plant, warning the buyers to reconsider.  And when your landscaper recommends this plant and buys it for you to install in your yard, you also should be notified.  Here they are:

But the two bamboo species on this list have been further restricted this year.  The State of Maryland now allows individual counties to regulate bamboo, including prohibiting its sale, planting, or allowing it to grow on another property without appropriate containment (barriers or trenches).  At this time, it does not appear the Anne Arundel County has regulated bamboo.

There is another list yet, that of noxious weeds.  While these are typically not sold or planted deliberately, the State of Maryland requires that these weeds not be allowed to produce seed.  Currently, the list is noxious weed includes seven species:

What has been a surprise to many attendees was that some of the invasives that we have battled in the Cape are not listed; I am thinking of English ivy (Hedera helix), Bushkiller (Cayratia japonica), Multiflora rose (Rosa multiflora) and Phragmites (Phragmites australis).  Of these, the first three are on a list of “additional plants to consider” (I expect, maybe to be added to the first two lists), but Phragmites is not even listed.  Plants we see often in nurseries that are also “plants to consider” include Japanese honeysuckle (Lonicera japonica), Leatherleaf mahonia (Mahonia bealei) common periwinkle (Vinca minor) orange-eye butterfly bush (Buddleja davidii) and I am sure that Stacey would find many more on this list that she would want to control… So, here is the entire list of “additional plants to consider”. 

Just remember that nobody’s perfect, and that we probably have planted some of these ourselves (oh, no!), or found them in our yard.  We only do what we can.  I know I have be guilty of planting Nandina (before it appeared on the list), and Periwinkle, before I was aware of these plants being an issue.  And I am proud to have removed and eradicated some other invasives in my yard (Bamboo, English ivy, and Wisteria.)  Let’s all give ourselves a pat on the back !