Uncarina GRANDIDIERI

Uncarina GRANDIDIERI - Grandidier's uncarina, Uncarina grandidieri, Mouse Trap Tree.

First flowering in just 2.5 months!

Uncarina is a genus in the family Pedaliaceae, also known as the sesame family. All species of the genus are endemic to Madagascar and grow in arid regions of the island with a subtropical climate.

The plants are caudiciform shrubs and small trees with a thickened trunk base. Leaves are simple, on long petioles, covered with dense pubescence; in large species the blade reaches 30-40 cm (12-16 in) across, while in miniature ones it does not exceed 10 cm (4 in).

The flowers are large, funnel-shaped, mostly yellow, rarely pink or white, with a dark throat. The fruit is a woody capsule set with long spines with curved hooks at the ends. All parts of the plant emit a distinctive odor when touched.

Grandidier's uncarina is the most famous species of the genus, named in honor of Alfred Grandidier, a French explorer of Madagascar.

The caudex forms very early and is already clearly visible two months after germination, while first flowering occurs in approximately two and a half months - an exceptional occurrence for caudiciform plants. Flowers are bright yellow, up to 6 cm (2.4 in) across, with an almost black throat. Under greenhouse conditions and with regular feeding, a seedling is capable of growing more than one and a half meters (5 ft) in a single summer.

Uncarina seeds are large, flat, with a dense seed coat. Before sowing, they are soaked for 12-24 hours in warm water or in a solution of a growth stimulant: SUPERthrive, HB-101, Aminosol, Epin, or Zircon until swollen. Scarification is usually not required, but very hard seeds benefit from being lightly filed on the side, away from the embryo.

Sowing is carried out in a sterile loose substrate of peat and sand to a depth of about 1.5 cm (0.6 in). The sowing is moistened from a spray bottle, covered with a transparent lid or placed in a propagator, and germinated at a temperature of 25-30 °C (77-86 °F), preferably with bottom heat.

Seedlings appear in 1-3 weeks, fairly uniformly. Sowings are ventilated daily and condensation is removed. Seedlings grow very quickly and display a caudex after just two months, so they are grown immediately in individual deep pots.

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The plant needs the brightest possible location with direct sun; in summer it is best taken outdoors.

Maintenance is warm during the growth period, optimally 22-30 °C (72-86 °F). In winter, during dormancy, the temperature is kept within 12-15 °C (54-59 °F). The plant does not tolerate frost.

Watering is regular during the period of active growth; between waterings the upper layer of the substrate dries out. With the onset of leaf drop, watering is gradually ceased, and during dormancy the caudex is kept dry.

The substrate must be loose and permeable, with a high proportion of coarse sand and perlite. Drainage is mandatory at the bottom of the pot, and a deep container is chosen.

Feeding with a balanced fertilizer is applied once every two weeks during the growth period: it is nutrition that determines the rate at which the plant gains size.

In a cramped pot growth slows down noticeably, so young plants are potted on as they fill the root ball. The canopy is shaped by pruning at the beginning of active growth; the plant tolerates it well.