These culprits come seemingly overnight. They lay low at first. Even their flowers hide, so tiny they are barely visible to the naked eye; yet they’re super-efficient at making seed, growing new generations in a matter of days.

Meet the prostrate, annual weeds that, as you read this article, might be invading any bare spot in your landscape.

Our recent rains have helped these invaders along. While they are capable of growing in the driest of soils, moisture makes it easier for them to spread. I have two species currently threatening world domination right in my front yard.

Prostrate spurge (Euphorbia maculata) is a very low-growing native to North America. The entire plant is hairy and grows in a ground-hugging mat. Like other Euphorbias, it produces a milky sap that can be an irritant to skin and eyes, so wear gloves when touching.

Sometimes it is referred to as spotted spurge, as some varieties have dark spotted leaves. This plant can grow anywhere sunny. It has a short life cycle and can produce viable seed within a few weeks of germination. Seed will germinate best at soil temperatures between 75-85 degrees, in full sun.

Management techniques can include removal by pulling or hoeing, followed by applying at least 2 inches of mulch on the infested area. Application of preemergent (prior to germination) or post-emergent herbicides may be effective, but you still need to mulch to prevent further seed germination after treatment.

Common purslane (Portulaca oleracea) is another ground-hugging annual plant that appears in mid to late summer. It is a succulent plant with fleshy leaves clustered at stem joints. Leaves are oval to spoon-shaped with a reddish margin. Very small yellow flowers typically open on hot sunny days. Stems are also fleshy and reddish. Purslane is not a North American native but has been here a long time — likely introduced in the16th century — and is very well established.

Management of purslane, like prostrate spurge, is a two- faceted process. One is control and removal of existing plants, hopefully before more seed is deposited. The second is preventing seed germination in the soil. Purslane is very easy to pull out; that is probably the fastest way to remove existing plants. Be sure to remove and throw away all of the plants. Stems reroot very easily, so don’t leave them behind. Don’t compost the plants; seeds can continue to mature even after the plant is removed from the ground, contaminating your compost with viable seed.

Application of 2 inches of mulch will discourage new seed germination. Preemergent herbicides can help, but post-emergent herbicides are only effective on very young plants. If these plants are a problem this year, early application of pre-emergent herbicides early next summer might be advisable.

There are other aggressive prostrate annual weeds; common examples are Black Medic, Prostrate Knotweed and Puncture Vine.

For more information on weed control, check out this resource.

Submit gardening questions to csumg2@elpasoco.com or call 719-520-7684. The in-person help desk is open 9 a.m.-noon and 1-4 p.m. Mondays and Wednesdays at 17 N. Spruce St. Find on Facebook at Colorado Master Gardeners – El Paso County.