It is a biennial or perennial herb. It is about 1 to 2 metres in height. The seed of digitalis are small in size, so they are mixed with sand for sowing. Leaves are collected in both the years but leaves collected when 2/3 of flowers are fully developed. The seedling is than transplanted into the field. Generally the leaves are collected in the early afternoon, with a belief that maximum cardio-active glycosides are present at that time.
The leaves are immediately dried after collection below 60 C and dried leaves are stored in airtight containers. The dried leaves should not contain more than 5% moisture, since it promotes hydrolysis of cardiac glycosides resulting in loss of cardiac activity.
Digitalis (Digitalis lanata Ehrh.)
Family: Scrophulariaceae
Varieties
Strain E.C. 115996 is reported to have higher foliage yield with high glycoside content
Soil and climate
A well drained sandy soil rich in organic matter and slightly acidic (pH 5.5 – 6.5) in reaction is suitable. It requires a cool and mild climate (20 – 30°C) and comes up well in hill slopes at elevation of above 1250m Mean Sea Level.
Planting season
Planting spreads from May – June for direct sowing and February for nursery sowing.
Sowing
Sow indoors in March to May or sow directly outdoors in May to June or September to October.Sow seeds on the surface of a peaty soil. Do not cover or bury seeds as the seed needs light to germinate, just press seeds lightly into the earth. Keep seed in constant moisture (not wet) they will usually germinate in 2 to 4 weeks at around 20°C (68°F).
Cultivation:
Digitalis purpurea foxgloves are biennial which means that plants establish and grow leaves in the first year, it will send up large spikes, then flower and produce seeds in the second.
As a rule, they are hardy plants and can cope with any soil unless it is very wet or very dry. They are fairly disease resistant, although the leaves may suffer slightly from powdery mildew if the summer is hot and humid.
If you cut the stalk down before it goes to seed, it will generally rebloom through August and, if you wish, you can reseed from the second showing.
Self-sown seedlings producing different shifting, untutored patterns of flowers each year, they can be easily transplanted to the location you want them to bloom. They are best transplanted when the leaves are about 10cm long. Make sure the newly moved plants are watered very well to help them establish.
Manuring
Apply FYM 10t/ha and NPK 20:30:30 kg/ha respectively as basal dose. Again N 150 kg/ha is applied as top dressing in 4 equal splits at 3 months interval.
Aftercultivation
Give 1 – 2 weedings in the initial stages.
Plant protection
Leaf spot and leaf blight
It can be controlled by spraying Mancozeb 2g/l.
Harvest
Harvesting extends upto 2 years. 8 – 10 cm long leaves (excluding petiole) are collected between July and August from the first year crop and second harvest taken one and half months later. Dry the leaves by passing hot air at 60°C. About 2 – 3 harvests can be done during the first year and 2 harvests during the second year.
Yield
About 2000 – 3000 kg of dried leaves/ha can be obtained. The active principle in dried leaves ranges about 0.44 to 0.71 per cent.
Medicinal Uses:
Digitalis is a classic example of a drug derived from a plant formerly used by folklorists and herbalists.
In 1775 an English physician named William Withering, acting on a account supplied by an herbal healer, reported that a tea made from it was useful in curing dropsy, the fluid accumulation often associated with heart-related problems. Since that time, the drug digitalin has become one of the old, generic drugs doctors consider the first line of defense against heart-related ailments.
Digitalis slows the heart but provides a source of medicine used by doctors in heart medicine. In pure form are referred to by common chemical names such as digitoxin or digoxin, or by brand names such as Lanoxin, or Purgoxin. Herbalists have largely abandoned its use because of its narrow therapeutic index and the difficulty of determining the amount of active drug in herbal preparations.
The whole foxglove plant is extremely poisonous. Fortunately it tastes very bitter and causes irritation of the mucous membranes in the mouth, actually causing pain and swelling. It also causes diarrhoea, nausea and vomiting, so if it does get in, it soon comes out. Because of these factors, it is not really a problem for wildlife, human or otherwise. However if you ever find a child who has been around this plant with symptoms of oral irritation, grab a stem or two and get to the emergency room.
Wear gloves when handling plants or seeds, plant only where children or animals will not have access.
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