Two years ago we had our 20-year-old landscaping re-done and were very happy with the sparkling new look. Little did we know that lurking in the trucked-in lovely black soil was an insidious invader disguised with attractive, ferny foliage: Poison hemlock. When they first emerged, I didn't know what they were, but was intrigued with the delightful foliage and let them grow. I do remember being puzzled about the measles-like rash on my arms and hands. Even after a botanist friend smilingly identified it, I kept them trimmed to 2 feet tall, until the foliage began turning brown in July, whereupon they succumbed to an application of Roundup.

Following is a description of hemlock and 3 other springtime invaders for which you might want to be on the alert.

WATER HEMLOCK Cicuta maculata

IDENTIFICATION – At a glance, the foliage resembles the herbs chervil, coriander and parsley. (Don't use it in your salads!) The best way to identify water hemlock is by the purple or red spots on the hollow main stem. Unfortunately, these spots often don't appear until the plant is mature. In summer, water hemlock blooms with lacy clusters of white flowers atop the 2- to 5-ft.-tall stems.

This is a highly poisonous perennial weed found from eastern Canada to as far west and south as New Mexico. All parts of water hemlock are poisonous. Eating even a small part of the stout taproot, which looks like a sweet potato or parsnip, can be fatal. So be sure to wear gloves when you weed, and wash your hands after handling it. One-year-old plants have a single taproot while older plants have clusters.

FAVORITE CONDITIONS – As you might guess from the name, this is mainly a water plant, found near ponds, streams and irrigation ditches. It doesn't show up in tilled gardens very often, but it can if the area is damp and rarely cultivated. And you'll find it in both sunny and shaded areas.

CONTROL – Wearing gloves, pull or dig out water hemlock as soon as you spot it. If you're not able to remove it by digging, cut the flowering stems off near the ground to prevent seeds. Systemic herbicides, such as Roundup™, are also effective. Apply the herbicide to the low rosette of leaves before the flowering stem stretches in summer.

APHIDS

IDENTIFICATION — Orange, green, yellow, red, brown, black or covered with a waxy white or gray coating — there are all kinds of aphids out there. Most are 1/16 to 1/8 in. long, although some are bigger.

DAMAGE — Most aphid species are specific to one kind of plant, but they all pierce plant tissue, then suck out fluids. You'll often find them in big clusters on new growth tips. A few aphids won't hurt anything, but the population can grow rapidly. Large numbers of aphids cause curling, distorted leaves, yellowing foliage and stunted growth. They may also transmit diseases from plant to plant. CONTROL — Keep an eye out for aphids. They reproduce so quickly that it takes no time at all before they're all over your plants. Don't over fertilize — high nitrogen causes lots of lush, tender new growth that attracts aphids. Prune out infested parts and dispose of them, or hose aphids off plants with a strong jet of water. Insecticidal soap controls aphids, but be sure to cover them completely with the spray. Parasitic wasps and ladybugs, aphid predators, feed on the pests. However, this control takes some time to work, so it isn't the best way to get rid of aphids quickly.

WILD MUSTARD Brassica kaber

IDENTIFICATION – Also known as charlock, wild mustard is found almost everywhere in the United States and Canada. In the spring, you can't miss the clusters of bright yellow, four-petaled flowers on plants with small bristles on the leaves and stems. You may have a harder time identifying the plant when the flowers are gone because the lower leaves don't always look the same. Sometimes they're lobed, but often they just have coarse teeth on the edges. In midsummer, the plants produce seeds in elongated pods with "beaks" at the end.

Wild mustard has a very short life cycle, acting as an annual or a winter annual (coming up in the fall, living through winter, and setting seed in spring). Wild mustard can be toxic to animals if they eat enough, although birds eat the seeds without ill effects.

FAVORITE CONDITIONS – You'll find this weed in sun just about anywhere in any soil — along the road, in gardens and among crops. Listed as a noxious weed in some northern states and Canada, it invades cultivated mustard and canola fields.

CONTROL – The seeds of wild mustard can stay viable in the ground for a long time, so it's important to pull or hoe it before it has a chance to set seed. As with most annuals, it's shallow-rooted, so it's easy to pull up the whole plant.

Botrytis gray mold

IDENTIFICATION — Botrytis gray mold usually appears during cool, wet weather in spring as small, wet-looking spots on tender new flower buds and blossoms. But it can spread to leaves and stems. Even fruits can be damaged. The spots grow larger and are often covered with gray fuzz. DAMAGE — Almost any plant can be stricken with botrytis gray mold. Flower buds don't open, fruits are spoiled and the plant is weakened by the disease.

CONTROL — Wind and rain spread the spores. So grow plants where air moves freely and don't wet flowers or foliage when you water. Bury infected plant parts 18 to 24 in. deep — don't put them in your compost pile. Several fungicides, including Maneb and Dicloran, are effective against botrytis gray mold.

Upcoming Gardening Events you'll enjoy:

Today (Saturday) May 9, 10:00 at Douglas Hart Nature Center – Darla Chouinard will instruct you about vermiculture (worm composting).

Saturday, May 16, 12 noon, East side of Old Main, EIU – Jon Collins will give a tree walk tour of the campus.

Saturday and Sunday, May 23 & 24, noon-5:00 at the Coles County Historical Society's 21^st Annual Garden Ramble at Wes Whiteside's 5 acre garden 2 miles east of Charleston just off Route 16. If you haven't visited Wes' garden, you're missing a wonderful experience. Master Gardeners will be selling plants, gloves, plant markers and gently-used gardening items. MG speakers will entertain you at 2 and 3:00 on interesting topics.

If you have any horticulture questions, call the U of I Extension office 345-7034. Volunteer
Master Gardeners are in the office on: Monday—2 to 4 p.m.; Wednesday and Friday—9-11 a.m.

This column is based on information and materials at the University of Illinois Extension office, located at 707 Windsor Road, Suite A., Charleston, 61920; phone 345-7034; or web site: www.extension.uiuc.edu/coles/