"Most Wanted" (to be rid of) Weeds

Late rains are good for the new natives that we planted in January, but they are also good for the weeds. Mustard (several different kinds), Maltese star thistle (also called tocalote), horehound, and weedy annual grasses are all thriving. So this Saturday (April 21, 9 - noon) at the park cleanup we will focus on pulling. Fortunately the soil is moist and they come out pretty easily. If you cannot make it on Saturday, stop down at the park at any old time and pull a few. If we all keep at it we will get there. The natives will take hold, and though we will always have to keep after the weeds, it should become more manageable over time (so says the optimist in me).

The protocol for weed control is to 'pull and leave' plants that do not have flowers and seeds. It is more important to get rid of these young plants than to keep everything neat and tidy. Just leave their roots exposed so they will dry out. The most important places to weed are around existing native plants and in the newly planted area in the center of the park, the mounds. Once we have made progress in these areas we can move to other heavily infested areas. And finally, do take care to avoid poison oak.

Poison oak. Do not pull, do not touch! Do not get into thicket unless you know this plant well and are sure you are not in it. If you do suspect that you touched it, wash immediately with cold water and soap.(I use Tecnu, a detergent, to remove the irritating oils. Available at most drugstores.)

Here are pictures of the “Most Wanted.” If you are unsure, don’t pull.

Tocalote or Maltese star thistle (Centaurea melitensis) is having a bumper year this year. As it matures the center stem elongates and yellow flowers with sharp thorns appear. Get rid of this wherever you see it!! (4/16/2012)

Tocalote infestation in nature park near the Arroyo Seco channel. (6/2011)

Tocalote flower (June 2003)

Weed friends: mustard on left, tocalote on right. If you don't think you can tell them apart, don't worry. Get rid of all plants that have toothed leaves in rosette shape. There are no natives in the park like them.

Tocalote.

Mustard

Young horehound (Marrubium vulgare). These are growing all over the mounds. Their seeds stick to clothing, shoes and dog fur. Pull them before they get a chance to make more seeds.

Mostly horehound and mustard on the mounds. Be careful not to pull the newly planted natives. 

This pretty little non-native, scarlet pimpernel (Anagallis arvensis), is quite common but not as problematic as many other non-native weeds. Better to spend your time pulling tocalote, mustard and horehound!

Scarlet pimpernel before going into bloom.

Wild radish (Raphanus raphanistrum)

Wild radish flower, kind of pretty, but pull it anyway.