Swallowtails are attracted to specific plants

Q. Which plants do swallowtail butterflies require?

A. Strikingly beautiful in coloration, with distinct tails on their hindwings, swallowtail butterflies are easily attracted to gardens, flying spring to fall in the suburbs. Here are six you are likely to find:

• Eastern tiger swallowtail (Papilio glaucus): Both male and female have black "tiger" stripes on the yellow background of their upper wings and have blue on their hindwings (more extensively on the female). Host plants of the caterpillar, or larva, are wild cherry, birch and ash trees. Adults (butterflies) sip nectar from wild cherry, lilac, Joe Pye weed and milkweed.

• Zebra swallowtail (Eurytides Marcellus): Both male and female have pale whitish-green wings with black stripes and very long hindwing tails with a central reddish stripe. Caterpillar hosts are young plants of the pawpaw family. Butterflies favor the flowers of blueberry, lilac, redbud and common milkweed.

• Giant swallowtails (Papilio cresphontes), the largest butterflies in the United States, have a wingspan of 4 to 6 inches. Its forewings have a diagonal band of yellow spots forming an "X" at the outer tip of the forewings. Its hindwings are black-edged and filled with yellow. Caterpillar host plants include the prickly ash and common rue, while adults feed on lantana, azalea, goldenrod and swamp milkweed.

The so-called "dark swallowtails" include:

• Pipevine swallowtail (Battus philenor), with a wingspan up to 3½ inches, is known by its hindwing of iridescent blue or blue-green above and its underside with a single row of seven round orange spots. Both surfaces of the fore wings are black or blackish-brown. Caterpillars use pipevines as their host plant. Butterflies feed on thistle, bergamot, lilac, dame's rocket and lantana.

• Black swallowtail (Papilio polyxenes) has black upper wings and a yellow band near the wing margins (males) or a row of yellow spots (females). Hosts plants for the caterpillar are plants of the parsley family (carrots, Queen Anne's lace). Adults favor red clover, milkweed and thistle.

• Spicebush swallowtail (Papilio Troilus) differs from most swallowtails because of its greenish cast. Males have mostly black upper wings with ivory spots on the forewing margin and hindwings flushed with green. Females are black with a bluish sheen and blue hindwings. Caterpillar hosts include the spicebush, sassafras and laurel trees. Adults feed on azalea, lantana, milkweed and thistle. Prized for its beauty, the male was featured on the U.S. Postal stamp of January, 2013.

­ - Arlene Swartzman

Q. My herbs are starting to flower. What should I do?

A. What you do with flowering herbs depends on why you are growing them.

If you are growing them for beauty with other annuals and perennials in your ornamental garden border, then leave them alone and admire them. Enjoy the fragrance. Add them to your garden bouquets. Put a few in a bud vase in a special spot inside.

If you are growing herbs to eat and enhance foods, cut off the flower immediately. The flower pulls flavor from the leaves and diminishes the taste. Cutting it off will direct flavor back to the leaves.

If you are growing the plants for seeds and new plants, let them go to flower. Harvest the seeds. Replant when you are ready.

If an herb flowers and you wanted it for cooking, don't panic. Remove the flowering top and even some of the uppermost leaves. The plant will put it's effort back into producing good tasting leaves.

Herbs that are stressed by drought or extreme heat may go to flower sooner.

Myself, I like growing herbs for all of these reasons - for beauty, for eating and for seeds. The important thing is to have fun growing them.

- Holly Schmidt

• Provided by Master Gardeners through the Master Gardener Answer Desk, Friendship Park Conservatory, Des Plaines. Call (847) 298-3502 or email northcookmg@gmail.com.