Get Adobe Flash player
story by claire schuchman Left unchecked, weeds and non-native plants will dig in and take over, becoming… S ALIENS IN YOUR GARDEN everal years ago, a client asked me to take a look at a Mt. Lebanon garden overwhelmed with two nasty weeds that spread aggres- sively and thrive in a variety of conditions—wild buttercup (rununculus), and bishop’s weed (aegepodium). Wild buttercup has a profuse yellow blooming stage in April and competes with spring growth of desirable forages. Bishop’s weed has a lovely variegated cultivar with a flower much like Queen Anne’s Lace (and in fact is still sold at local garden centers.) However, when it flowers and subsequently sets seed, birds carry the seeds and drop them on the ground in their own little fertilizer caplets, where they germinate. The new plant is not the lovely variegated form, but reverts to the original green form. Both weeds rob other plants of valuable fertilizer. These monsters—both among the long list of invasive species in Pennsylvania—require chemi- cal warfare, and even then success is fleeting. There was no need to inform this client of how onerous these pests are—the damage to her garden was the proof she needed. The roots were entwined in every shrub and perennial she has, choking the life out of everything. She would love to be rid of them, and after sending my crew in to fight the good fight for more than five years now by hand pulling, careful spraying and even painting full-strength herbicide concentrate on the plants with a paint brush, we are not even close to being successful. So what to do? When it comes to invasive plants, sometimes drastic measures are called for. One commercial client’s land- scape was overrun with two other invasives—wild morning glory (convolvulus arvensis) and thistle, (cirsium discolor). We concluded that the only way to solve this unsightly problem once and for all was to take everything out of the bed, dispose of it and put the bed on a spraying program by a qualified professional. The client lost thousands of dollars in plants. 44 mtl • march 2013 After a full year of careful spraying, we finally were able to plant up the bed last spring. How did the problem get this bad? In this case, the client had eliminated the chemical weed program offered by his landscaper. He saved money in the short run but paid a higher price in the long run. So, what is the definition of an invasive plant and why should we care? “Invasive plant” defines a species that has become a weed or a pest. These plants grow and spread in a fiercely aggressive fashion, displacing other plants. They either spread roots that travel several feet underground and send up new plants as they go or grow from seeds that disperse easily, such as dandelions. The worst offenders do both. They are not picky about soil com- position or pH and exploit disturbed ground. Highway projects and construction sites, where wild morning glory and thistle arrive first, are common problem places. Both not only spread voraciously by seed, but also have spreading roots up to eight feet long. No amount of hand pulling will solve this problem. Because invasive plants are almost impossible to control, they can dominate entire areas. A good case in point is the Japanese knotweed (fallopia japonica) taking over along Banksville Road. According to Amy Delach at Defenders of Wildlife, a national conservation organization focused on wildlife and habitat con- servation and the safeguarding of biodiversity, the cost to control invasive species and the damages they inflict upon property and natural resources in the U.S. is about $137 billion per year! That’s a lot of money, and much of it is tax dollars.  Most invasives came here from other countries and are often called “exotic,” “alien,” “introduced” or “non-native.” Some were actually brought here to solve problems. According to the website www.Oregon.gov, kudzu which is an aggres- sive vine literally destroying entire forests in the south by