Portugese Kale

 

Portugese Kale - Brassica oleracea var. costata

Looking for a new and nutritious vegetable to plant in the garden?  Try Portuguese kale, also known as Portuguese cabbage or couve tronchuda.   It is a common and important food in the Portuguese diet and is found only in Portugal or in regions with a strong Portuguese influence like Hawai`i.  It’s different from the traditional round cabbage. Looking more like collards, these plants are leafier, having round leaves with thick, white ribs and grow to 2 ft. or more across.

Portuguese kale has a delicious, mild sweet flavor. It is an essential ingredient for the authentic caldo verde, a winter staple and favorite soup in Portugal. In most recipes, the broth is thickened with mashed potatoes,  beans or pasta, and spiced up with onions and garlic, linguica or smoked pork loin. The large leaves are quite flexible and when blanched are easy to wrap around meat, rice or vegetable fillings.

Because this cabbage forms only a very loose head, it’s convenient to pick only the outside leaves a few at a time. If crowded, it becomes leggy and produces fewer and smaller leaves.  The plant can tolerate a coastal exposure so it will grow  near the beach or along the cliffs.

Finding seed – many times it is listed under ethnic vegetables as Portuguese cabbage or Portuguese kale. Try Kitchen Garden Seeds (www.kitchengardenseeds.com, 860-567-6086) and Redwood City Seeds (www.ecoseeds.com, 650-325-7333).

Hummingbirds and Pollination

 

About 25% of plants are wind pollinated. The rest rely on pollinators: bees, bats, beetles, butterflies and yes, hummingbirds, as well as some other birds. During the day hummingbirds feed about every 10 minutes and consume up to 2/3 of their body weight from the nectar of plants; they can service 20 flowers per minute. The wings of hummingbirds beat up to 55 beats per second and allow these tiny birds to fly at speeds up to 50 mph. They can hover and even fly backwards or upside down. 

Hummingbirds are primarily attracted to tubular flowers. They are stimulated by color, especially the color red. Clumps of bright red, orange and pink flowers are more visible to them than other colors. Plants with red, tubular shaped flowers are an excellent choice in the garden to attract hummingbirds. Other plants that attract these birds are gladiolus, honeysuckle, iris, lupine, nasturtium, petunia, and cosmos. 

Recently, I was asked if hummingbirds pollinate vegetables. I am having difficulty finding specific vegetables that they pollinate. That’s probably because there are not many vegetables with red, tubular shaped flowers, which attract the hummingbirds.  

Lastly, the Islands of Hawaii have no hummingbirds, but a one inch moth is often mistaken for this tiny pollinator. The hummingbird moth has grey beating wings with a quiet humming sound. Unlike like other moths, this fellow is diurnal and uses his long proboscis to ingest nectar from plants and flowers.  Hawaii's hummingbird moth is also a pollinator! 

Photo: University of Maine

The Plague of Powdery Mildew

Powdery mildew (PM) is a menace to many gardeners. The disease will turn large zucchini leaves white and later brown. A whitish cast will appear on many common garden plants such as tomatoes, beans, cucumbers, mustard, peas, and collards. Infected leaves often turn yellow to brown and may shrivel making the plant unproductive and eventually die.

The white fungal growth can develop both on the upper and the lower surfaces of the leaf, and sometimes, on flowers and fruit. The cottony like threads of this fungus travel along the surface of the leaf, occasionally sending “roots” down into the leaf tissue in order to obtain nutrients.

Many different types of powdery mildew fungi are host specific. This means that one particular mildew fungus will only infect those plants in a particular genus or family; the PM on the beans will not attack papaya, and the PM on mangoes will not attack tomatoes. 

The fungus likes temperatures between 60 and 80 degrees F being sensitive to temperatures above 90. Cool days and warm nights favor the disease. Spores of the pathogen are dispersed readily by wind. Even though this disease flourishes with high humidity, wet leaves can actually inhibit germination of the fungal spores, thus preventing infection. Because of this, the disease should be minimized during periods of heavy rainfall. Also during this time, the numerous spores that are on the leaves will be washed away.

Control – Stopping powdery mildew in its earliest stages of development provides the best control. This can be done by sanitation: remove and destroy infected parts of the plant. Other measures of control are as follows: plant in the sunniest locations, provide good air circulation through pruning, and avoid excessive applications of fertilizer.

Fortunately there are a number of relatively safe and effective materials to use against this fungus - wettable sulfur, horticultural oils, including neem, and Kaligreen (potassium bicarbonate a relative of baking soda). Serenade is a biological fungicide, a bacterium, that helps prevent the powdery mildew from infecting the plant. Cucurbits (melon, squash, cucumbers) can be sensitive to sulfur.  Do not apply when the temperature is near or over 90 degrees and do not apply within 2 weeks of an oil spray. Use these materials in the earliest stages of disease development for best results.  Before spraying, it would help to remove the leaves that are heavily infested.  Do not dispose of them on the ground since they are loaded with fungal spores. Powdery mildews can attack healthy plants; but older plants, less vigorous plants and those that are stressed are more susceptible to infection.  

Most important, choose plant varieties (vegetables, fruit trees and ornamentals) which are tolerant or resistant to the powdery mildew fungus. For more information about seeds from locally developed vegetable varieties, contact the University of Hawai‘i at Manoa: http://www.ctahr.hawaii.edu/seed/seeds.asp. Or, contact your local university cooperative extension office. Note: Some of the resistant varieties will exhibit powdery mildew symptoms, but the disease is less severe. 

Photos: Cornell University, Colorado State University and USDA