CO-Horts Blog

Monday, April 23, 2018

It's a Weedy Spring

Posted by Mary Small
Colorado Master Gardener State Coordinator
It’s spring and I have weeds. Rather, my landscape does. Both annuals and perennials are making their appearance – but I thought we’d look at a few annuals in this post. Remember that annual plants germinate from seed, grow, flower and go to seed in one years’ time.

Mouseear chickweed
This particular one (Mouseear chickweed – Cerastium vulgatum) is a newer resident on the property and seems to be adapting quite well to this gravel strip between the sidewalk and driveway.
Chickweed is a winter annual, meaning that it germinates in the fall and grows in early spring.  The stems and leaves are sticky from glandular secretions.  In addition, they’re weak and break easily, often leaving part of the plant behind. Meaning rummaging around in the gravel is needed (in this case) to get the whole thing out.

Incidentally, this is a good example of why gravel mulch laid over landscape fabric is not a great idea from a weed management perspective.  Wind blows soil around and eventually  it filters into the gravel on top of the landscape fabric. Wind- blown seed germinates and grows in the soil.  If the roots stay on top of the fabric, plants are usually not too difficult to pull. But if they move into the underlying soil, say through an opening in the fabric, they’re a lot harder and more time consuming to remove.
Prickly lettuce. Note prickles on centermost leaves.
The next weed is prickly lettuce (Lactuca serriola). This is a summer annual – which means it germinates and emerges in the spring or early summer.  It’s easy to pull out when young. The root system is quite small and there’s often a central stem to grab onto. It’s harder to pull when mature, though, and often breaks off at the soil line. Gloves are a necessity at this point, too - it’s not named prickly lettuce for nothing! This weed  grows rapidly in a short period of time. Watch for the ones you missed early hiding in shrubs or perennials throughout the season. Can you find it in the photo of the pansies below?
Prickly lettuce hiding in pansies

Shepherd's purse with tubular seed capsules
Can I just say I really dislike shepherd’s purse (Capsella bursa-pastoris)? That’s because this winter annual is often up and running on the south side of the house before I’m even thinking about weeds. Fortunately, they’re easy to pull due to a shallow root system. Shepherd’s purse has some interesting common names like Mother’s heart and  Witches’ pouches. Those names must be a reference to the interesting- looking, heart-shaped pods some of these plants possess.

Henbit (Lamium amplexicaule) – another winter annual - at least has pretty purple-pink flowers going for it. Henbit is a member of the mint family with square stems. Unlike many other mint family members, though, the root system is mercifully shallow and easy to pull in the spring.

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