Prostrate problems? Hints to tackle problematic weeds in your garden

FRANKLIN COUNTY — No medical advice here. Instead, I refer to the low-growing (prostrate), sprawling growth form of some of the weeds plaguing our yards and gardens. Knowing what you’re up against will help you invest resources where they will do the most good. The following are some of the more challenging ‘flat landers’ we battle.

Common Purslane (Portulaca oleracea): This fleshy succulent thrives in flower beds and gardens that have sporadic weeding efforts (like most of ours). It has fat, rubbery leaves with reddish margins and reddish stems. Flowers are small and yellow but mostly inconspicuous. Purslane is a summer annual that reproduces from seed every year. Early herbicide applications miss this weed because it doesn’t start growing until temperatures rise. Remove existing plants early and often to prevent seed production. Get rid of the plants as stems can root if left on moist soil. Seeds will continue to germinate throughout much of the summer. A pre-emergent like trifluralin (Preen) can be very helpful but you must remove all existing weeds and leave the soil surface undisturbed following application.

Spotted spurge (Euphorbia maculata): This has a similar appearance to purslane but lacks the fleshy leaves. Its flowers are pink to white but similarly inconspicuous. Spotted spurge, sometimes called prostrate spurge, tends to appear later than purslane and is much easier to weed out. It is also a summer annual. It exudes milky sap when stems are broken. This sap can be irritating to skin and eyes. Remove current weeds and dispose of them to eliminate as many seeds as possible. Pre-emergent herbicide is again a big help.

Prostrate knotweed (Polygonum aviculare): More similar in appearance to spurge than to purslane, this weed tends to a more recumbent vining habit. Flowers are small and white. You tend to see this one more often in driveways, sidewalk cracks, and in weaker areas of lawn. Once again this is a summer annual. Herbicide application might be personally gratifying, but it won’t do anything to control prostrate knotweed if it is not done before seed production. Depending on the location, glyphosate or 2, 4-D + dicamba will control plants that are already growing. Pre-emergent herbicides of the ‘weed and feed’ type can help with control in lawn settings.

Field bindweed (Convolvulus arvensis): You are probably all too familiar with this weed. Descriptive adjectives are best left unpublished. Bindweed, often called morning glory, is a perennial so fall herbicide application can be very beneficial. Glyphosate and dicamba can offer some of the best control but don’t expect elimination. Roots capable of producing new shoots are found to depths of 14 feet. Fragments of roots and rhizomes as short as 2 inches can form new plants. Fall is a great time to hit its root reserves hard. Pulling vines frequently and consistently will help over time. Every time you remove shoot growth you deplete root reserves. Keep at it and in time you will see much less bindweed.

Common mallow (Malva neglecta): This low-growing weed can be annual or perennial depending on conditions. You may know it as cheese weed, marshmallow weed, or bellybutton weed. Its leaves are circular with wavy margins. Flowers are pink to white and characteristic seed pods are round and flattened. Juvenile weeds can be chemically or mechanically controlled with relative ease. Mature plants have a deep taproot and, for the most part, seem able to live through any herbicides thrown at them. Herbicides containing dicamba offer your best control, but it has enough soil activity that it should not be used on flower beds or gardens. Where you can you’re better off using a knife or shovel to sever the taproot of mature plants.

There are less-common creepers, some of which include black medic, puncture vine, and henbit. All are annual weeds. Black medic is related to clover and alfalfa and is mostly a lawn nuisance. Henbit germinates in the fall earlier herbicide treatments often handle this weed. Puncture vine is the bane of bike tires and bare feet. Its twin-horned seedpod gives it the moniker goat head. Sandy soils are its preference. All efforts to eliminate seeds need to be taken. Herbicide containing Chlorosulfuron is best at preventing germination in roadways and other non-crop areas.