To really know a plant, one must kill it three times, or so it has been said. That may be true, but there are plants I would like to kill—just once!
RED FLAG WORDS. Here are some clues I wish I had paid more attention to before adding certain plants to my yard:
“Give space,” “spreads by roots,” and “grows anywhere” are sure-fire indications that this plant or tree may take over, requiring constant whacking or digging, possibly spreading well beyond your yard.
“Dwarf” too is an elusive concept. These plants may turn into behemoths, perhaps requiring only a bit longer than the full-sized versions before bullying their neighbors.
“Self sows,” “naturalizes readily,” and “spreads freely” are euphemisms for some plants that will turn up in every nook and cranny of your yard—or the entire neighborhood´s.
Strange looks from nursery personnel and questions like, “You really want to buy this?” are dead giveaways for trouble to come.
DON´T EVEN THINK ABOUT PLANTING THESE THUGS. Let these guys go in your yard and even your neighbors´ neighbors may be sorry. Beware, these plants are sometimes sold in nurseries, and seeds or plants are available via the Internet. This is in spite of their being outrageous invasives, often spreading into wild lands.
• Periwinkle (Vinca major) spreads into ditches and other waterways.
• English ivy (Hedera helix) tendrils can pry loose bricks and siding. Birds carry the seeds into wetlands where it smothers trees and understory plants.
• Tree of heaven (Ailanthus altissima) spreads by wide-ranging, seemingly invincible roots; then delivers a double whammy with copious seeds. The resulting trees now blanket many local hillsides.
• Scotch and Spanish broom (Cytisus scoparius/C. junceum) with yellow flowers, forms dense thickets obliterating plant and animal communities.
• Pampas grass (Cortederia selloana) with white seed plumes is also an abundant seed producer with resulting plants creating a fire hazard. It can send its seeds many miles via wind and birds.
IFFY PLANTS. I´m easily captivated by graceful or colorful leaves and flowers, and by plants that attract birds, butterflies, and other pollinators. Here are a few I find worth growing, but segregated away from less assertive plants:
• Milkweeds (Asclepias) are essential for survival of Monarch butterfly larvae. I take great pleasure in watching these colorful caterpillars chewing the leaves. However, most milkweeds will eventually take over the entire bed if permitted to do so, spreading by both seeds and roots.
• Fennel produces seeds that are favorites of finches and bushtits, and its leaves are a mainstay for swallowtail butterfly larvae. Fennel is often listed as a true invasive plant, so be careful. On the other hand, I find bronze fennel (Foeniculum vulgare purpura) to be a reluctant spreader.
• Tansy, with its charming button flowers, also spews forth seeds. However, T. niveim, with soft grey/green leaves, appears much less aggressive.
• Love in a mist (Nigella damascena) is grown for its blue blossoms, and its seedpods are used in dried flower arrangements. But, I once let it go to seed and I´m still yanking it out years later.
• Locust trees (Robinia), also have attractive flowers but, look out, they will likely send up robust suckers all over the yard.
SPREADING PLANTS WELL WORTH THE EFFORT. These plants enthusiastically self sow, but are excellent garden additions and pull out with ease when they are finished blooming:
• California poppies welcome spring and entice bumblebees into a pollen gathering frenzy. I wouldn´t be without them!
• Verbena bonariensis, is a five foot tall, willowy verbena with lavender flowers that draws hummingbirds and butterflies, and produces seeds for finches as well.
• Honeywort (Cerinte major ‘Purpurascens´) is among the first flowers in the spring, abuzz with hummers and bees.
• Popcorn impatiens (Impatiens balfourii) flourishes in moist shade, again providing food for hummers and bees.
Conditions in your yard are no doubt different, varying with elevation, exposure, and soil. Even so, some spreaders are well worth the trouble; others aren´t. But do stay away from the real thugs; they´re truly bad news! See you in the garden.
Throwing caution to the winds, Sonora Master Gardener Vera Strader has recently added “dwarf” versions of barberry, lilac, and bottlebrush to her yard.
Schedule Change: Please note, the Master Gardener herb demonstration scheduled for September 2 has been rescheduled for October 28. Demonstrations resume September 9 with “Make a copper pipe trellis,” followed by September 16, “Composting,” September 23, “Paper your garden to prevent weeds,” and September 30, “Bamboo Arts and Crafts.” All demonstrations are held in the demonstration garden at the Cassina High Dome; all are on Saturdays and start at 10:00 am. Pre-registration is not required.