Previous month:
April 2008
Next month:
June 2008

Insect Helpers

Early May 2008 047 copy Recently I promised to show a photo of a soldier beetle. Here it is, cleaning up the pahids that were eating my Rosa chinensis. This is the first one I have seen in my San Francisco garden, though I have seen them several times in the East Bay. A colleague at City College tells me that they are often in his Noe Valley garden.

There are over 100 species of soldier beetles in California. The larvae feed under bark or in soil litter on eggs and larvae of butterflies, beetles, moths and other insects. The adults of some species eat pollen and nectar, but the adults of other species eat aphids and insect eggs and larvae. In this case you can see the shed skins of aphids on the stem of the rose bud, but I think the soldier beetle ate up all the aphids and was just wandering around hoping for more. As soon as I saw the soldier beetle, I ran back in the house for my camera, and when I got back it was gone. I was sure it had flown away , but I waited, and soon it wandered back into view.

You can recognize soldier beetles by their narrow shape, and by their soft black, gray, or brown wing covers and often a red, orange, or yellow head and abdomen. All these details are from the Natural Enemies Handbook, by Mary Louise Flint and Steve Dreistadt, Statewide Integrated Pest Management Project, 1998.

Soldier beetles are just one of many naturally-occuring helpful insects that show up when you avoid the pesiticides that kill them along with pests. You don't buy soldier beetles, just give them a chance to help you.


Heat, Wind, Rain...

Here in San Francisco, our weather reporters make much from small changes. Tomorrow, they may say, will be clear after morning fog, with slightly cooler than average temperatures. The next day will be the same but maybe a little breezy. The past few weeks have given them a little more to talk about. First it was hot. This happens a few times each spring and summer, but the first heat spell of spring is the plant killer. The days are almost at their longest, the plants that grow most in in the spring have lots of young, tender growth, or maybe they are covered with flowers. And the soil is drying. This spring the soil was particularly dry, since we have had no rain for some weeks. Then we had those hot days. Was it only two? I witnessed a beautiful rhododendron, in a shady site on the north side of a house, with beautiful balls of pink flowers go from that to a plant covered with sad, withering flowers, in the course of one afternoon. My own cinerarias suffered, with some, in a part of the garden that was driest, wilting so that the purple daisies never recovered. I watered all afternoon.

Then came the wind. It was so windy last week in the College garden that I thought better of transplanting the chayotes (finally) into their spots by the new arbor. OK, I'll do it next week. They are looking good, though, waiting in the wings, in the lathe house, but I think so much wind would have caused them to wilt.

And then, last Saturday, rain! What a surprise, after many dry weeks. We had only a little rain in San Francisco, but maybe there was more in other parts of the Bay Area. The snails stayed out in full view in the morning rain, allowing a very good snail hunt. The lettuce and arugula were nicely crisp. The garden seems to appreciate a rain more than a watering. But the bigger surprise is the snow in the mountains. Ten inches in the Sierra, at the end of May!

Today we are back to seasonally mild weather, followed by a foggy evening. A good day for gardening.

I don't know if it is due to the dry mid spring, or to what, but I am seeing more lady beetles than usual this spring. I rarely garden for more than a few minutes without seeing one or maybe more. And in my camera is a photo of a soldier beetle, another aphid eater. I will try to get it into the next post.


A Weed to Watch Out For

Mid_april_2008_068_copy My Golden Gate Gardening column in today's SF Chronicle (www.sfgate.com) was about Nothoscordum gracile, a weed to watch out for in your garden. I thought I would put a few photos in this post, for those who wonder if they have it and to help you understand what is going on underground if you do have it. The plant, shown at left, has white flowers that look a little like a brodiaea. It blooms most actively in summer. The leaves are strap-like, gray green, and do not have a midrib. This plant is not edible and does not have any scent of onion or garlic. The plants can be easily overlooked, but the best way to control them is to remove the first one you see, digging carefully to get all of the root and the bulblets, even discarding a handful of soil to be sure you got rid of all the bulblets.

Mid_april_2008_008_copy

Here is a mature bulb with its many bulblets, each the size of a grain of rice. The youngest ones are white, so they stand out well against the soil, but the older ones turn brown, and are very difficult to see. The bulbs are usually very deep in the soil--as deep as your shovel can reach. Be sure your shovel blade is straight up and down when it enters the soil, or you may cut the stem of the plant, leaving the bulb unmolested in the soil.

Mid_april_2008_069_copy The problem with leaving some of the bulblets in the soil is that they will all germinate into small plants. Incompletely digging a Nothoscordum bulb, and then turning the soil in the bed can spread the bulblets all over, so that soon you will practically have a lawn of the plants. I am combating this weed now in a vegetable garden, digging out mature bulbs and also digging the smaller plants carefully to be sure I have removed the attached bulbs, and am ruing the day I tolerated the first plant of it. Don't make the same mistake.