|Plate XII: MYSORE RASPBERRY, Rubus niveus|
The plant is a large scrambling shrub growing 10 to 15 ft (3-4.5 m) high, with cylindrical, flexible stems downy when young, later purple, coated with a white bloom. It is thoroughly set with sharp, hooked thorns. The leaves, 4 to 8 in (10-20 cm) long, are composed of 5 to 9 elliptic-ovate leaflets 1 to 2 1/2 in (2.5-6.25 cm) long, coarsely toothed, dark-green above and, on the underside, white-hairy with small, sharp spines along the rachis, petiole and midrib. Pink or red-purple, 5-petalled flowers, 1/2 in (1.25 cm) across, occur in lax axillary and terminal clusters. The fruit is rounded-conical, flat at the base; compound, made up of individual drupelets; red when unripe, purple-black when ripe, with a very fine bloom; 1/2 to 3/4 in (1.25-2 cm) in diameter, juicy and of sweet, rich black-raspberry flavor. The clusters may contain as many as 2 dozen or even more. The seeds are small and not objectionable.
Origin and Distribution
The species is native to Burma and India, particularly the lower Himalayas, from Punjab to Assam, the Deccan peninsula, and the Western Ghats; and is common in the evergreen forests of Mahabaleshwar. The more hairy var. horsfieldii Focke extends south through Malaya to Indonesia and Bontoc and Benguet in the Philippines. From India, the Mysore raspberry was introduced into Kenya, East Africa, and has been grown in the mountains there for many years. Seeds from Kenya were obtained by F. B. Harrington of Natal, South Africa, in 1947. In 1948, he supplied seeds to the University of Florida's Agricultural Research and Education Center, Homestead. The resulting seedlings were planted out in 1949 and fruited so well the following winter that plants were distributed to many experimenters throughout south and central Florida. By 1952, many nurseries were offering the plants for sale and had difficulty filling the demand. By 1955, a major supermarket in Lake Worth was selling the fruits by the pint. In 1955, the University of Puerto Rico received planting material from Florida and established plantings in the central-western mountains of that island.
In Florida, some interest was still alive in 1965, but early enthusiasm waned as homeowners neglected their raspberry bushes, growth became too rampant, picking more and more difficult among the tangle of thorny canes, and birds competed eagerly for the crop. Many plantings were destroyed, and few remain.
This raspberry has a remarkable climatic range in Asia, from the relatively warm altitude of 1,500 ft (450 m) to the temperate environment at 10,000 ft (3,000 m). In Florida, brief drops in temperature to 35º F (1.67º C) have done the plants no harm but 20º F (-1.67º C) has killed young, tender growth, and prolonged freezing weather has killed the plants to the ground or outright.
In Florida, the plant flourishes on limestone or acid sand. In Puerto Rico it is grown on lateritic Alonso clay with a pH of 5.0. Good drainage is essential.
The Mysore raspberry is often grown from seed but germination is slow and irregular (from 3 weeks to several months), and the seedlings are subject to damping-off. Germination can be expedited by pre-treatment with concentrated sulphuric acid. Stem cuttings root well, but the preferred method of propagation is by tip-layering. They develop plentiful roots in 3 to 4 weeks.
Florida gardeners place the plants 2 1/2 to 4 ft (0.75-1.2 m)apart in rows 6 to 8 ft (1.8-2.4 m) apart supported by 2 or 3 strands of wire attached to end-posts. In Puerto Rico, the plants are set out in hills spaced 6 to 8 ft (1.8-2.4 m) apart each way. If taller than 18 in (45 cm), they are cut back, surrounded by 2 or 3 stakes 6 ft (1.8 m) high linked by crosswires. As the canes grow, they are loosely tied to the stakes and wires. A mulch is desirable to retain Moisture and control weeds.
During the first year, in Puerto Rico, the plants are given 1 to 2 oz (28-56 g) each of ammonium sulfate quarterly. Thereafter, a 9-10-5 fertilizer formula is applied quarterly, 4 to 6 oz (113-170 g) per plant.
On Florida limestone, the recommended fertilizer consisting of 4-8-4 or 4-7-5 NPK with 3 to 4% magnesium and 30 to 40% organic nitrogen is applied every 2 to 3 weeks. And it is considered highly desirable that a mixture of zinc, copper and manganese be sprayed on the underside of the leaves 3 to 4 times per year.
Irrigation is necessary in dry seasons. Old canes should be cut to the ground at the end of the fruiting period and there should be severe pruning and thinning out in the late fall to force new growth for a winter-spring crop.
The Mysore raspberry tends to bloom and fruit throughout the year but summer fruits are of poor size and quality. Therefore, the seasonal pruning has the additional purpose of preventing spring and summer flowering and allowing the first blooms to appear in December. Thus managed, the fruits are borne continuously from about February to May or June.
The fruits should be harvested only when they are not wet from dew or rain and when they are fully ripe and separate easily from the receptacle which remains on the plant. Gathering should be done at least 2 or 3 times a week to avoid losses by falling and spoilage. The fruits are highly perishable and should be consumed or processed as soon as possible.
In full sun, the crop is light. Where the plants receive some light shade in the afternoon, the yield is heavy. A single plant may yield 2,400 to 3,000 fruits over a 4-month period. A plot of 8 test plants in Florida produced 50 lbs (22.5 kg) in one season.
Pests and Diseases
The 2-spotted mite, Tetranychus bimaculatus, congregates on the underside of the leaves of shade-grown seedlings, turning them yellow. Occasionally, flower buds and fruits are attacked by the green stink bug, Nezara viridula, also called pumpkin or squash bug.
Anthracnose (Elsinoe veneta) causes spotting and scabbing of the canes toward the end of the fruiting season. Affected canes should be cut off and destroyed to prevent further infection. Damping-off of seedlings can be avoided by planting seeds in a mixture of peat moss and vermiculite, or in sphagnum moss.
The fruits are enjoyed fresh, alone or served with sugar and cream or ice cream. They are excellent for making pie, tarts, jam and jelly. The fresh fruits can be quick-frozen for future use.