idenifying an invasive plant

Asked March 1, 2017, 1:49 PM EST

How can I tell if my mahonia is mahonia bealei or mahonia aquifolium (OR grape holly)? As I understand it, the former is an invasive while the latter is not. Pictures show them looking very much alike. I bought the plants at Behnke's nursery in Beltsville and vaguely remember them being bealei, but I'm not sure. If I do have an invasive mahonia, what action should I take. Mine is a smallish city garden. I'd hate to lose these plants that can live in shade under a silver maple and are now 5" feet tall, but even more to harm the environment

Baltimore Maryland

3 Responses

You can send us digital photos of the shrub and we can make an identification. Send us photos of the whole shrub and flowers.

Mahonia bealei, leatherleaf mahonia is becoming increasingly invasive in the wild and in domestic landscapes. Some species of birds relish the blue berries of Leatherleaf mahonia and spread it. It can tolerate poor conditions and shade. A distinguishing feature are the Flowers. Long spires of flowers can start upright and then hang down and develop into huge clusters of grape like berries. Remove this shrub if possible. Otherwise, prune off the fruit so birds do not spread it.

Mahonia aquifolium,
Oregon grape holly is actually a smaller-leaved mahonia that is native to Oregon and British Columbia, though not native to Maryland. It is not as common as the leatherleaf mahonia and has not proven to be invasive here. Flowers are yellow in tight clusters around the shrub.

Photos attached to help with ID. Does the location matter in deciding whether to uproot invasives--that is, proximity to areas where naturalizing is likely? Thx for your help so far.

Please take a look at this link from Ohio State University which details Mahonia aquifolium:

How tall is it and does yours get many berries? The spreading flower type makes yours look more like Mahonia bealei.

Right now, in our most recent version of the Plant Invaders of Mid-Atlantic Natural Areas, this is a ''Plant to Watch" as it has shown up in wild, natural areas. See here:
If yours does set lots of berries, we'd suggest removing them if you like and plan to keep the shrubs.