The Downside of Native Plants

If your garden is big enough to run magnificently wild, you'll be fine. But if your garden is smaller and well-manicured, watch out! The beauty and vigor of native plants that are happy there comes at a price—the constant struggle to keep them in check.

This blog post was born as, with growing astonishment, I reeled in yard after yard after yard of multiple runners of native California pipevine (Aristolochia californicaTorr.), hand over hand. If I hadn't, in short order a wholefenceline of desirable plants would have wound up smothered in its big, soft leaves. In January, I was thrilled to see the vine's trellis covered with little brown “pipes.” I allowed it free rein in a large neighboring bush, while clipping errant tendrils I noticed heading in other directions. Only when I happened to lift some of the thick mulch along thefenceline did the scope ofpipevine'sinvasiveness hit home! Moreover, thepipevine went to seed this fall, which will make things worse. I've got a resident monster that will require perpetual monitoring and pruning of runners and seedpods.

Pipevine flowers, January

The very first eye-opener came ten years ago, when I planted a bed of native showy milkweed, Asclepias speciosa Torr., to establish a monarch breeding site. (Not even one caterpillar, so far.) The milkweed grew tall, bore huge leaves and lovely bunches of fragrant flowers—and proceeded to fall over onto every other plant within a five-foot radius! I've since controlled this competitive gambit by placing large tomato frames around each clump of sprouting milkweed stems. More startling was that milkweed sprouts appeared all over the garden, as far as twenty feet from the Mother Ship. I must constantly pluck them out of our bark mulch open space and from among other plants. Obviously, the milkweed's subterranean connections are nearly as impressive as the pipevine's surface ones. Starting that first year, I've pruned off the immature milkweed seedpods, alarmed at the thought of spreading by that means, too.

Pipevine in gooseberry, April

This spring, the milkweed sprouted through a thick blanket of California fuchsia, Epilobium canum (Greene) P.H.Raven, that in its third year is starting to overrun the milkweed bed and much else besides. I've been ripping it out at the edges so as to spare adjacent plants. That too will be an ongoing task.

CA fuchsia overrunning milkweed bed, April

Don't get me wrong—I love these plants, and am glad they're in my garden. But if you assume, as I did, that native plants will be low-maintenance, think again. We establish them with their water-wise and wildlife advantages in mind—from monarch butterflies to hummingbirds—and want them to thrive. But the trade off for them doing well may be the unending challenge of reining them in. 

Photos: all taken by Patricia Matteson

1)    Pipevine flowers, January

2)    Pipevine in gooseberry shrub, April

3)    California fuchsia overrunning milkweed bed, April

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