Species: Two kinds of hens and chicks!|
The word chickweed is often used to refer to two distinct species: common chickweed (which exists primarily as a winter annual) and mouseear chickweed (perennial species). They are similar in appearance, but mouseear chickweed leaves and stems are densely hairy, whereas common chickweed plants lack hairs. Mouseear chickweed is also able to root at nodes of the stems. These two species are not sisters, but closer to "kissing cousins"; that is, common chickweed is Stellaria media, whereas mouseear chickweed is Cerastium vulgatum. Four Stellaria species and eight Cerastium species are found in Illinois, but most people refer to them all simply as chickweed. Turf specialists separate the chickweeds, but the different species react similarly to most herbicides. Common chickweed is more common (hence the name) than mouseear chickweed, but both species occur throughout Illinois.
The name henbit is used for two Lamium sisters, henbit and purple deadnettle. Henbit (L. amplexicaule) is common throughout Illinois, whereas purple deadnettle (L. purpureum) appears occasionally in the southern half of Illinois. Both henbits exist as winter annuals and are commonly found in reduced-tillage fields. The lower leaves of henbit are petiolate (attached to the stem with petioles) and its upper leaves grasp the stem (lack petioles), whereas all leaves of purple deadnettle are petiolate. Henbit flowers are usually a darker pink to purple color than the flowers of purple deadnettle.
Mustard (Brassicaceae) is a family of many species, but several dominate the Illinois scene. Mustards are often divided by flower color. Wild mustard and yellow rocket have showy, yellow flowers, whereas shepherd's-purse, field pennycress, and pepperweeds (Virginia and field) have smaller, white flowers. All these mustard species are present in untilled fields, but shepherd's-purse is usually less of a problem. Illinois has many mustards, however, and these do not cover the "water front" by any means. One plant that may often be mistaken for a mustard is butterweed (Senecio glabellus), which belongs to the aster (Aster-aceae) family. Butterweed has bright yellow flowers and exists as a winter annual, so it often flowers close to the time the true mustards flower.
A mild winter provides winter annuals (chickweed, henbit, mustards, etc.) an ideal environment for early season growth. This can currently be seen in many fields where no spring tillage has occurred, and particularly in no-till where the weeds appear motile (spreading). Small seeds left on the soil surface with crop residue! What could be better for a weed home?
We discussed no-till knockdown treatments in a previous issue of the Bulletin (No. 3, Table 5), where mustard was listed but not chickweed and henbit. Herbicide ratings for these species can be found in Tables 2 and 8 in Chapter 3 of the 1999 Illinois Agricultural Pest Management Handbook ("Weed Control for Small Grains, Pastures, and Forages"). Information in these tables can provide some hints for their control. The relevant parts of those tables are shown here in Table 2.--Marshal McGlamery, Aaron Hager