SPECIALTY CUT FLOWER CORNER: For the beginning grower

Flowers and insects: a manageable combination
Sure, insects cause flower growers some noticeable heartaches, but they can be controlled organically—with beneficials, diversity, selecting the right flowers for your region, and even with guinea hens.

By Melanie DeVault

Pickin' Bugs: Guinea fowl have a good reputation for keeping flower beds pest-free--and they can be trained (or so they say).

That said, everyone has had their heart broken. My fall silky Asclepias (Asclepias curassavica) -- two nice, long rows that I had babied from seed and planted out at the beginning of July for a great show at market on those balmy, autumn Sundays in Emmaus, PA -- were my heartbreak. With the usual craziness of fall produce and flower sales and readying the high tunnels for winter, the Asclepias didn’t get checked close enough or often enough. Pretty soon, a gooey yellow scarf enveloped every stem so thickly they were a total loss. Aphids. Thousands of aphids. So we gingerly pulled all the plants -- and started more dried arrangements to make up for the loss. Aside from aphids in the high tunnel on one small row of sunflowers near the door (others in the same high tunnel center were untouched and I was able to wash the aphids off, dunking them in a bucket of water), we have had no major insect problems on flowers. Ever. We had a few Japanese beetles, a few cucumber beetles and a few inch worms that entertain from the Ageratum. That’s it.
Diversity and good soil make a difference.

Lynn Byczynski, grower and author of The Flower Farmer (www.growingformarket.com), says grasshoppers are her number one problem in Kansas. “We’ve found them to be unperturbed by anything we have unleashed on them, including Nosema locustae and Beauveria bassiana.” That's Latin for beneficials/biological controls which are labeled for grasshoppers and are organically acceptable. “Grasshoppers are highly attracted to certain species of plants including dahlias, mums and marigolds, so we don’t even try to grow those anymore.”

Then, like all growers, Byczynski adds, “This year, we will try guineas on the advice of many Growing for Market readers. But we won’t know for a while whether our super-hoppers will be controlled by these voracious birds.” We inherited a few pretty tame guineas at Pheasant Hill Farm last year and they love working within eyesight of us. We’re hoping they get all the ticks, Japanese beetles and other insects that might bother our flowers. We intend to train them with white millet this spring to go where the bugs might go. (For more information on guineas, see Jeannette S. Ferguson’s book Gardening With Guineas or visit her website at www.guineafowl.com where you can even hear them.) Guineas also eat a lot of weed seed. Down side can be noise and their traveling habit, but, supposedly, can be trained. We’ll see.

Besides grasshoppers, other insects, Byczynski says, are really only a minor inconvenience on her cut flower crops. “Part of that is because we have an ‘organic attitude’ about fitting our farming into the ecosystem. For example, we grow dill, fennel and Asclepias for bouquets. But we are happy to defer to the monarch and swallowtail butterflies when their need for food arises. We just leave these plants in the garden, let them get munched down by the caterpillars and then enjoy the spectacle of metamorphosis.”

Steve Bogash, regional commercial horticulture educator in Central Pennsylvania, says flowers generally ARE pretty easy and low on insect problems. “The way you grow out flowers as a small grower is so different from large monoculture, you see different problems,” adds Bogash, Franklin County Cooperative Extension agent and former grower. “Small growers with diversified crops will have an incredible mix of insects that will eat each other before there are problems.”

What’s Easiest To Grow with Insects in Mind?

There are lots of good, easy ones, say Dr. Stanton Gill, with Central Maryland Research and Education Center, Maryland Cooperative Extension. He, and Bogash named some of my favorites: Sunflowers, Zinnia, Karma dahlia, Celosia, tall Ageratum, Statice, and Salvia leucantha.

SUNFLOWERS -- Succession planted from March and going until frost (longer if you have a high tunnel and extra protection), sunflowers don’t have many insect problems. Gill notes that you may see some adult striped or spotted cucumber beetle damage as the season progresses -- they can do damage to the petals. While they don’t destroy the plant, they do destroy their value as a cut flower. The solution: Don’t grow cucumber plants, or other veggies the pests love, in the area. You can use Neem oil, a tropical-tree extract, that kills many pests on contact, he says. (Certified organic growers should check their latest catalog or www.omri.org for current status of organically approved pesticides). At Pheasant Hill Farm, we cut the sunflowers as the first rays open, especially if there seems to be a problem with beetle damage, and keep the sunflowers in the cooler. If you miss a few flowers with a hole or two (not impossibly chewed flowers) give the flowers away to kids at the farmers’ market. They’ll be thrilled. So will Mom.

ZINNIAS -- The garden workhorse isn’t usually bothered by insects or pests. We often find those nasty, big spiders making fascinating webs between them here and there. Actually they’re Orb-web spiders, yellow and black argiope, and they are working for you, so work around them. Japanese beetles can sometimes hit zinnias, Gill says.

KARMA DAHLIA -- I recommend these highly (see previous column on Karmas). Bogash loves them. Gill says in some areas, people have problems with grasshoppers (especially if there are high grasses or fields are nearby), cucumber beetle, and leafhopper.

Others mentioned include Celosia (especially wheat), Ageratum, Statice and Salvia leucantha which have very few insect problems, Gill says. Gill also recommends Liatris, Sedum (Autumn Beauty), Tuberose, Phlox paniculata and Lisianthus as of little interest to insect pests (but bear in mind lissies are hard to start). Trachelium caeruleum, lavender to dark blue flowers borne in panicles at the end of the stem, are also relatively pest free, he says.

What Are the Biggest Problems for Flowers?

Insects that can be a problem for flowers include aphids, thrips, spider mites, leafhoppers, beetles and caterpillars, says Bogash. “They can often be controlled with natural parasites and predators.” While beneficial insects can be bought from biological control companies and through many catalogs, the alluring descriptions can be daunting. Both Gill and Bogash say beneficials work better in a greenhouse setting. In fact, Bogash says in a closed system, beneficials work very well. In tunnels, they can be competitive. “Large predators, lacewings, ladybugs don’t like being around each other. Maintaining sanctuaries, giving them a place to go, helps.” For beneficials, various catalogs and websites tell you how many you will need, when to release and what to expect, including IPM Laboratories, Inc., www.ipmlabs.com. The Association of Natural Bio-control Producers web lists distributors in the U.S. at www.anbp.org.

Another resource for the flower grower fighting insect pests is the sticky trap, yellow or blue cards (available at many nursery centers and through many seed and greenhouse catalogs) with a brightly colored surface coated on both sides with a special sticky, non-drying glue. These traps will catch many insects and can help you with monitoring them. Unfortunately, they’ll also trap beneficial insects. They’re especially useful in the greenhouse environment.

Part 2 >>