Growing Concerns 569: True red perennial, info on garden pests

Seeking the true red perennial flower can be a   long term pursuit


Dear Janet,

I have been searching for a true red flowering perennial for years now. Not really interested in lilies, but something that gets about 18-24 inches high and would bloom most of the season. Any suggestions? Oh- I've tried bee balm but they don't seem to come back after 2 years, and they are not as true of a red color as I hoped for. - D. -

Dear D.,

Red is a tough goal in perennials. You can call a meeting of ten gardeners, have each bring their best red flower and get ten different hues ranging from red-orange to red-violet. Gardeners themselves are often surprised at how non-red their flowers look once they are not in situ among leaves of a given color but held up against other "reds."

There are no perennials that bloom all season. The longest blooming perennials provide flower for about 7 weeks, 3 or 4 weeks of which will be non-peak display and may require deadheading to achieve. So you will need not just one but at least four or five perennial species to have red throughout the growing season.

A red primrose (Primula polyanthes) followed by tulips, an oriental poppy (Papaver orientale), coral bells (Heuchera sanguinea), 'Fire King' yarrow, an astilbe of your choice (I like 'Glut' but then I call the bluer reds the truer reds) and winding up with a hardy hibiscus (H. moscheutos, a red variety) might be the best you can do, although that mix would start shorter and end taller than your desired size. Perhaps other readers will have suggestions, which I'll pass along. The fun is in the effort!

Short reports

A reason to choose your weeds

As a professional gardener I often must neglect my yard in favor of client's beds. This means there will be many weeds in my garden each June when I turn my attention there, so I've literally chosen some of those weeds to help make the problem manageable.

My weeds of choice are pretty things grown for their ability to light a smile while shading out less desirable weeds. Examples are love in a mist (Nigella damescena), spiderflower (Cleome hasslerana), policeman's helmet (Impatiens glandulifera) and perilla (P. frutescens). These annual flowers, available as seed or plants at many garden centers, spread seed where they have once been grown. They come up thick and to the near-exclusion of more troublesome weeds in spots where I have not yet been able to weed or mulch.

Leaves suddenly stripped from your columbine?

A sawfly that specializes in columbine is probably to blame. Look closely because these insects are exactly the color of the leaf in their columbine-eating, caterpillar-like larval stage. They are easily squished or killed with insecticidal soap. However, those tactics are best employed early in May when the infestation starts and the insects are tiny. If your plants are leafless already, just cut them back and let them grow new foliage.

Stalking the stem borer

Many perennials such as lily (bulb-type Lilium), aster, delphinium, Helen's flower, hollyhock, obedient plant and phlox are attractive to the same insect that bores into corn stalks. If you see the tip of a flower stalk wilting, look for an insect larva inside the stem at the base of the wilted portion. Clip off that part of the stem and destroy it.

Don't despair. In most cases you haven't lost the bloom, you've just pinched the plant and encouraged it to produce multiple flowering stems.

Spraying to prevent the damage isn't worth the costs in time, pesticide or consequences to the delicate balance of life in the garden. This insect doesn't cause that much harm and doesn't occur in quantity in a diverse, healthy garden. However, it does have such wide tastes that you would have to keep applying an insecticide on everything throughout May and June to poison relatively few, scattered caterpillars as they first begin to chew their way into stems.

Spare that painted lady caterpillar!

This caterpillar also affects the stem tip but it doesn't bore in. It knits the top leaves together on its chosen plant, which may be one of many species including globe thistle, aster or hollyhock. In the protection of that tent it feeds on the growing tip, creating an increasingly noticeable, messy packet of frass -- caterpillar droppings.

Painted lady butterfly is Vanessa cardui, as pretty as its name, boldly patterned orange and brown. It's often raised and sold for children's science projects.

This insect, too, does no lasting damage. Plants can complete their growth and bloom well after the caterpillars have gone.


Green thumbs up

to the intensity of color in early season foliage. It's delightful to see, as beautiful as a floral display. All the rain that has caused such trouble on some fronts has also given us one of the most intensely colored Mays I can recall.


Green thumbs down

to thinking that we're the only ones who enjoy fresh new leaves. If you had an insect problem on a plant last year, watch it closely now for signs of infestation. You can nip it in the bud more easily than you can correct it later.

 Originally published 6/5/04