Edible Ornamental Plants

In frontier times, people foraged the  nearby hills and fields for edible plants. Since the early 1900’s, however, Americans began the great migration to the cities and  eventually lost their foraging ability. Perhaps the time has now come to learn which ornamental plants and common weeds can be a  good source of nutritious food.

Here is a short list of some well-known edibles. Many university websites have a more comprehensive list of ornamental edibles.

A. Weeds - If you can’t beat them, eat them!

 1. Dandelions, Taraxacum officinale -Fresh dandelion leaves can be eaten raw, in salads, added to a stir fry, or boiled and steamed like spinach. They have a bitter taste, but boiling will help take that out. Dandelions also make a great addition to soups and stew. They are high in carotenes, iron, calcium and vitamins A and C. As a detoxifying agent, dandelions aid with liver, urinary and gall bladder disorders, diabetes and high blood pressure. Dandelion root tea is sold in local health food stores. 

2. Lamb’s quarters (Chenopodium album) is also called wild spinach with similar nutritional value to spinach. 

3. Burdock (Arctium Lappa) is a weed rich in potassium, iron and calcium. 

4. Common mallow (Malva neglecta) the leaves, stems, and immature seeds are eaten raw or cooked. Mallow is reported to be rich in calcium, magnesium, potassium, iron, selenium, and vitamins A and C.

 5. Purslane (Portulaca oleracea) is a succulent; the leaves, stems and flowers can be eaten either fresh or cooked. The leaves contain more omega-3 fatty acids than any other leafy vegetable plant.

Other edible weeds include chickweed, white and red clovers and plantain.

B. Edible Flowers

1. Marigolds are one of the most commonly grown ornamental annuals. When dried and crumbled, the petals of marigolds can substitute for the most expensive spice in the world: saffron. 

2. Roses, both the petals and the rosehips (fruit), are edible. Rose water is often used in scones, cakes, sherbets, salads and icings.  

 3. Sunflowers – in addition to the commonly eaten seeds, the petals can be added to soups and stir-fry dishes. The sunflower buds can be steamed and eaten like an artichoke.

4. Daylilies (Hemerocallis sp.) - Some species (especially H. fulva) are cultivated in Asia for their edible flowers. The petals can be eaten raw or more commonly dried and used as a flavoring in soups. The young shoots should be cooked and have a pleasant sweet flavor. Even the roots are edible.

Nasturtium, violas, borage and calendula flowers are also edible and frequently used in salads.  Bon Appetit! 

Caution: Before collecting, research the plant to verify it is edible, and more importantly, make sure it is properly identified. Eating the wrong plant can be disastrous.

Mulch with Wood Chips

 Mulch placed around plants is a good way to conserve soil moisture. Plants that have a layer of mulch over their roots will manage better in a drought situation. Wood chips, when available, make an excellent mulch for other reasons also. 

• A wood mulch layer can help prevent diseases by keeping fruit like strawberries and tomatoes, from touching the fungal infested ground. The same mulch layer will create a barrier, preventing rot causing fungal spores from splashing up onto low growing citrus fruit. Wood mulches also produce chemical compounds that inhibit the growth of disease causing fungi. Furthermore, a layer of mulch will help to control erosion and reduce weeds. Apply at least 4 inches for good weed control.

When incorporating large quantities of non-composted wood products like sawdust and wood chips into the soil, it’s a good idea to add a little high nitrogen fertilizer to prevent a nitrogen deficiency.  This can happen because bacteria require nitrogen as they break down the wood and will take it from the soil. It is only temporary though, because as the bacteria die, they will release the nitrogen. This is especially important for newly planted annuals like flowers and vegetables. Established trees and shrubs, however, have a large enough root system to obtain nitrogen from deeper depths.

Lawn - the Control of Weeds

Broadleaf weeds appear in the grass.

Controlling weeds in the lawn should begin long before chemical herbicide applications are considered. Cultural measures ought to be employed from the beginning. These include: 

• Proper irrigation -  weeds often invade lawns that are either over-watered or under-watered. Perhaps the worst possible irrigation schedule, yet common, is daily watering for 5–10 minutes. Light, frequent irrigation creates a shallow-rooted lawn which is more susceptible to weed invasion, as well as being less tolerant to drought.  In dry areas, where irrigation is employed, water should penetrate to a depth of 6 to 8 inches. The best practice is to allow the soil to partially dry out between irrigation. The top 1 to 2 inches  should be fairly dry before watering again. For more information on irrigating lawns, see UH CTAHR publication, “Watering Lawns”, at http://www.ctahr.hawaii.edu/site/info.aspx

• Proper fertilization – apply suitable amounts of fertilizer on a regular basis; nitrogen is the key nutrient for turf.

• Proper mowing heights – each turfgrass species has an appropriate mowing height. Mowing some grasses too short can weaken the lawn and predispose it to weed invasion.  A typical guide is to remove no more than one-third of the leaf blade at each mowing. If too much is removed, it will take more time for the grass to recover, giving weeds a chance to invade.

• Thatch is a layer of organic matter - stems, stolons, roots - that develops between the turfgrass blades and the soil surface. Regular thatch removal will help keep turfgrass healthy and competitive with weeds.  For Hawaii residents, see the UH CTAHR publication “Removing Thatch from your Lawn” for more information on this procedure.

• Any activities that lead to soil compaction will contribute significantly to turfgrass stress. This in turn, will make it easier for weeds to invade. These activities may include heavy foot traffic as well as vehicles traveling over the area.

 100% weed control in the lawn is impractical. Weeds will occur, but the problems can be minimized with a well-managed, vigorously growing lawn. By combining cultural methods with herbicide applications when needed, weeds will  be minimized.

For chemical control, a grassy weed in a lawn is difficult since most chemicals cannot distinguish between good and bad grass species. Fortunately, certain herbicides can distinguish between grassy plants and broadleaves. It is the chemical composition of the herbicide and the morphology of the plant that will cause certain herbicides to affect broadleaf plants but not affect grasses. Therefore, controlling broadleaf weeds in a grassy environment is relatively easy. Purchase an herbicide with the active ingredient 2,4-D, MCPP (mecoprop), or dicamba (Banvel). These products are often sold in combination, giving better management and a wider spectrum of the broadleaf weeds controlled.

For light weed infestations, spot treating is more appropriate than treating the entire lawn. Apply just enough of the solution to wet the leaf, do not apply to the point that the herbicide is dripping off the leaf. To insure maximum absorption, stop mowing 2 or 3 days before treatment and allow 3 or 4 days before mowing again. This allows sufficient time for the weeds to absorb the herbicide and transport it to their roots.

Caution: these materials are volitle, espectially 2,4-D. The drift can damage other valued broadleaf plants; tomatoes and hibiscus are particularly sensitive.