Two inquiries received by e-mail, both dealing with unwanted garden intruders, are the focus of this week’s column.
!folo!Q: Deer have eaten the flowers and leaves from our rose bushes. What is the best way to bring the bushes back to health. Should we prune them back?
– Ernest Zeilberger
A: I am less concerned about your roses than the deer that are grazing on them. Due to conservation efforts, there are now several million deer in California, and they make themselves at home wherever wilderness still borders back yards, including the canyons and hillsides throughout Los Angeles and Southern California.
Like any other pest control problem, deer deterrence is a matter of perseverance, especially if you want to keep down costs and do not want to fence your property. For years, the only deer repellents on the market were meant to be sprayed on surrounding structures or wild vegetation, rather than in the garden itself. Chief among them were coyote and mountain lion urine concoctions, the logic being that deer would stay away from the scent of their predators.
Today, there are a host of nontoxic, organic products that are meant to be sprayed directly on your garden plants. Some repellents, such as “Not Tonight, Deer,” can even be sprayed on vegetable plants. Search the Internet under `Deer Repellent’ to read up on available products together with testimonials about their effectiveness. These spray-on repellents require application from once a day to once every three months.
Roses are strong plants that will recover soon enough from the radical pruning administered by your neighborhood deer. If you wish, prune them evenly, in the shape of a vase, as you would prune them at winter’s end. Due to our warm fall climate, there is no reason you should not continue to see blooms for another two months.
You only want to make sure that your bushes have not been nibbled back below the bud union. Roses are grafted plants. This means that the variety of your choice – let’s say the fragrant “Mr. Lincoln” – has been grafted to a rootstock variety. The location of the graft, or bud union, is noticeable as a bulge in the trunk one or two inches above the soil line. As long as the deer munch on “Mr. Lincoln” above the bud union, “Mr. Lincoln” will grow back and you will continue to harvest fragrant roses. However, should your roses be devoured to beneath the bud union, you will still get roses from rootstock suckers, but they will not be of much interest. Typically, roses growing out from rootstocks are medium size, wine red in color, and without fragrance.
Q: My problem is with what seems to be a parasitic plant of some sort. The parasite seems to be springing from two different sets of plants – a grouping of Baby’s Blanket (Thymus serpyllum) and a group of Blue Mist Shrubs (Caryopteris). These two sets of plants are in different areas of the same garden plot. Orangish strands wrap themselves around the plants. They appear to spring out of the plant itself, with no point of apparent origination. At some points, there are little whitish “berries” that almost look like mistletoe. I have attempted to get rid of it by cutting the plants back below the lowest area of infection, but a couple of days later, there is more. This thing is driving me crazy!
– Kristie Daigle
A: Your plants are being victimized by dodder. (Cuscuta is its botanical name.) You are correct in calling it a parasite. It twines its way around plants and sends haustoria, which are rootlike structures, into your plants’ vascular systems, sucking up water and minerals from your plants’ xylem, and taking in sugars from your plants’ phloem.
Some say that the only way to kill dodder is to spray it with herbicide which, unfortunately, kills the host plant as well. However, if you are careful, you could don rubber gloves and take a thin artist’s paintbrush, dip it into a contact, nonsystemic herbicide and paint it onto the dodder, taking care to exclude herbicide from the garden ornamentals around which the dodder is wrapped. As a preventive measure, you should also consider pre-emergent herbicide. You apply pre-emergent herbicide to the soil and it prevents seeds, including dodder seeds, from sprouting. Contact and pre-emergent herbicides should both be available at any well-stocked nursery or home and garden center.
TIP OF THE WEEK: In response to a reader’s desire for orange Peruvian lilies (Alstroemeria), reported here several weeks ago, Grace Hampton wrote that packets of orange Peruvian lily seed are available through Park Seed. For a free catalog, call (800) 213-0076 or visit their Web site at www.parkseed.com.