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Weekend Science Fun: What We Can Learn From Weeds

Wherever and whenever you plant a garden, you have to expect some “plants out of place” or weeds to follow. Before you rip them out, remember weeds aren’t always just nuisances. Spend some time getting to know weeds and you might find they have something to offer.

Weed Activities with Children

1.    Plant identification

One of the first things young children need to learn when they grow a garden is how to identify the various vegetables, flowers and weeds. I’m sure we all have heard family stories about the time the beets got weeded out and the dandelions were left behind. Identifying tiny seedlings is no mean feat, and so learning to observe and identify plant characteristics is key.

Start pointing out things like leaf color, shape, the presence of hairs on the stems, etc. Did you know the name for dandelion comes from “teeth of the lion” and refers to the jagged teeth on the leaf margin? A simple fact like that might help a child remember what a dandelion looks like. Let some of the weeds go to flower so you can see what the entire plant cycle looks like. (Try not to let it spread seeds though).

dandelion

Save some samples of plants from the garden by pressing them. A leaf press is a useful piece of equipment for studying plants, and also for pressing flowers for crafts. An old telephone book can be a handy substitute if you don’t have a press. Or if you are handy, you can make one like this:

 

Identify the plants you find by looking in plant books or online for identification guides. Don’t be afraid to ask for expert help. Many counties have Master Gardener programs. The Master Gardeners are volunteers who help answer gardening questions for the public.

2.    How do weeds measure up to vegetables and flowers?

Compare growth rates of various plants, including weeds by measuring the height of the plants at weekly intervals with a yardstick or tape measure. Take pictures. How many inches does the weed grow versus the garden plant? Which one emerges from the ground first? Which one is ready to flower first? Do you think the weeds might shade the vegetables or compete with them for food and water? Why or why not?

3. Are weeds useful at all?

A weed is basically a plant out of place. If it was growing somewhere besides your garden, it might have some uses. How might a weed be useful?

I think most people have heard of eating dandelion greens. In fact, I saw some dandelion greens at the store the other day for $4.99 a pound. What about garlic mustard? The Brooklyn Botanical Garden has this article Garlic Mustard—A Palatable Pest about how to identify the weed and suggestions for preparing it.

My maternal grandmother studied botany. She often ate plants others considered to be weeds, because she knew how to accurately identify plants and knew which ones were edible at which stages. Just remember, certain weeds are poisonous, so learn from an expert before trying to eat anything new.

Notice whether any wildlife in the area feeds on the plants your think of as weeds. My dad was going to mow a patch of common milkweeds last summer but I showed him how insects feed on the leaves. I heard reports that later in the summer he was proudly showing the neighbors all the beautiful butterflies visiting “his” milkweed patch.

As long as they aren’t introduced/invasive species, many so-called weeds are really wildflowers in disguise.

sowthistle

Bug of the Week: Oleander Aphid

Oleander aphids, Aphis nerii, are bright yellow and black insects found feeding both on oleanders and various species of milkweeds. Interestingly, both milkweeds and oleanders are poisonous.

See if you can notice something about the next few pictures of oleander aphids on our desert milkweed.

oleander aphids

oleander aphids

oleander aphids

Both my son and I noticed right away that the aphids are all crowded on the new growth, which is rather reddish in color.
aphid wasp
Aphid colonies, as they are called, are often hotbeds of intrigue and danger. A tiny parasitic wasp is attacking the aphids on this branch (see just below the cluster of aphids). The wasp lays her eggs within the body of the aphids. The larva of the wasp feeds inside the aphid, eventually turning it into a brown, hardened structure called a “mummy.”

oleander aphids

The coppery brown circles towards the bottom of the colony are mummies. Inside the mummy the wasp pupates. Eventually the adult wasp cuts a hole through the mummy and emerges into the world.

Although usually merely regarded as garden pests, aphids are actually interesting creatures, They are also food for a number of different forms of wildlife. I leave these aphids alone because I know that the wasps, lady beetles and flower flies that feed on the oleander aphids will also feed on any other aphids drifiting into my garden.

Academy of Science and Technology Blog Carnival

Don’t you just love blog carnivals? What a wonderful way to get to know other blogs and learn more about science. This week the Academy of Science and Technology 1 blog carnival gets underway at Kim’s Play Place. Be sure to visit, the photos from the telescope are really cool. And stop by and find out about the Great Sunflower Project, too.

And if you are interested in children’s books, take a peek at my newest blog Wrapped in Foil.

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