A weed is sometimes defined as any plant growing in the wrong place. Perhaps an even better definition of a weed is a plant for which we have not found a use. For example, while returning from Brazil through Florida, we had an opportunity to stay a few days in Miami. I was surprised to see one of our native plants, the beach naupaka, or Scaevola sericea, growing along the coastal sand dunes of Miami Beach. It was being used for erosion control.
Our native was even used in hanging planters of multistory buildings. Landscapers love it because it is so hardy and attractive, but some folks were upset with its use because it wasn’t a south Florida native. On the other hand, native plant lovers of Florida are desperately attempting to save the mangrove forests along the coast because they are essential to coastal protection and are considered the nurseries for fish, shrimp and other sea creatures. In the past, they were used in Hawaii for the same reason, especially on Oahu near Kaneohe and Molokai where soil erosion was allowing mud into the bays and killing reef life. The mangroves filtered out the mud, thus protecting the reefs. Now, the tide has turned, so to speak, and folks are attempting to eradicate the mangroves in Hawaii.
My grandfather believed that God created it all, and it was good. If we don’t see the good, it is just that we haven’t yet figured out its value. Unfortunately, we sometimes find plants are used in an inappropriate manner. Then they may be referred to as weeds. Examples of this are the tobacco plant, coca plant, marijuana and even grains that produce alcohol. The plant is not intrinsically evil; people have misused it. The digitalis plant may be used to poison someone but in the proper amount, it can be used to save lives. My grandfather pointed out that good and bad are really human morality issues. Folks have good and bad behaviors or make good and bad decisions. Plants and animals may be used in a certain way, but we really can’t blame them. It is an issue of our management of the world around us.
A banyan tree in the park is great, but when one sprouts in your roof gutter, we call it a weed. Weeds in lawns are usually the result of poor management. Lawns injured by insects, fungus or nematodes will readily become infested with weeds. Improper mowing, watering and fertilization will lead to a weedy lawn. Don’t blame the weeds for a poor lawn. They are often just a symptom of improper maintenance practices.
When it comes to turf, high-quality, weed-free cuttings or seeds, properly established, are important. Soil that is not infested with perennial weeds like nut grass is also a basis for preventing weeds in a new lawn. After that, proper management practices that result in a dense, vigorous turf will aid in preventing weeds. Once weeds get established in lawns, they are difficult to get control.
Product availability is changing so fast with pesticide misuse concerns that it is difficult to make general recommendations. Check with your local garden shop for solutions to specific problems.
There are four important “rights” related to the application of herbicides. These are: the right material, at the right time, in the right amount, applied in the right way. Understanding all the instructions of an herbicide label to be sure it will control your specific problem without injuring your plants is as vital as using the right amounts. Safety margins may be smaller than you think. To apply pesticides in the right way, you must choose equipment that will give proper coverage. Spray jars that attach to your garden hose are good where you need to apply nutritional sprays, fungicides or insecticides to the lawn or garden. However, with weed killers, it’s a better idea to use a small 2- to 3-gallon tank sprayer. A tank sprayer is vital since hose attachments are not accurate enough.
If you end up having to pull weeds by hand, smile. Let’s take a positive approach to “weeds.”
Plants we often label as weeds are usually types that appear wherever the soil has been disturbed. It is nature’s way to heal wounds caused by landslides, fire and humans or their activities. Pig damage is a big issue wherever they have been allowed to breed without control. Disturbed land is ideal for weeds or pioneer species to thrive. They grow rapidly and often compete with what we may consider more desirable species. They produce large quantities of seed, and they are often difficult to control. Weeds are often described as undesired plants, plants growing out of place or plants that are a nuisance. Both the characteristics and the definitions of weeds emphasize that they are plants closely related to man. They come and go as man or his animals disturb the soil. Just as man has traveled and dominated the land, so have these species benefited from his activities.
Because of their origin being so close to the activities of man, many of the plants we call weeds have been discovered to be edible or medicinal and are used as pot herbs throughout the world. Many of the tasty ingredients in Thai food, for instance, are thought of as weeds by Westerners.
When you go out to pull weeds, it’s easier if you know they could be for dinner or to heal the sick. And so you don’t fall into the trap of calling them bad, think of them as pioneer plants for which we haven’t found the use.
One of our most common weeds is the Spanish needle, Bidens pilosa. The young shoots may be boiled and used as a vegetable dish, in salads or stews. The leaves can also be dried and cooked later. Many grasses are edible, especially the rapidly growing sprouts or shoots of larger growing types. Bamboo is an example.
The common purslane, or portulaca, has leaves and tender shoots that can be eaten raw in salads or cooked.
The familiar cattails of swampy areas are a source of several kinds of food. The starchy tubers are edible as young flower spikes. Young leaves are also eaten.
To learn more about the more than 100 edible “weeds,” check out “Edible Leaves of the Tropics” by Franklin Martin and Ruth M. Ruberte of the Mayaguez Institute of Tropical Agriculture.
I have also noticed that our local kahunas and some folks who have recently migrated from Southeast Asia really know a lot about edibles and medicinal plants that we think of as weeds, so tap their knowledge when possible.
For a change and perhaps for more peace of mind, let’s back off the concept of war with plants and try to see that there is good and beauty in all things. At the same time, let’s focus on keeping potential new invasive pioneer species from being introduced to Hawaii’s delicate ecosystem. Once here, they are almost impossible to eradicate. The species that have been established here for a long time are probably here to stay. They can and should be managed to minimize negative impact, but with limited financial resources, it is probably better to improve and support incoming agricultural inspection. We should also learn to see the beauty and possibly the value of what is already here.