Chondrosum gracile

Cultivation Details

Chondrosum gracile is found from the cold temperate regions of southern Canada, through the mountain ranges of N. America, south to the more tropical regions of southern Mexico. One report says that it is not hardy in the colder areas of the temperate zone, tolerating temperatures down to between -5 and -10°c^[1], though judging by its native range it should be much hardier than this^[PFAF]. Whilst plants in the south of its range may not experience frosts, in the north it can experience temperatures as low as -40°c^[2]. The plant requires a minimum annual precipitation of 200 - 380mm, this occurring in the spring and early summer, whilst in some parts of its range annual precipitation can be up to 1,000mm^[2]. Easily grown in full sun on any well-drained, dry to moist soil^{[1, 3]}. Tolerates a wide range of soils, except poorly-drained, wet ones^[3]. Prefers a near-neutral or lime-free soil^[1]. Established plants are very drought tolerant^{[3, 2]}. When grown as an ornamental, the plant is usually cut to the ground in late winter before the new shoots appear^[3].. Seed production is generally low, but may be plentiful in favourable years. Seed yields of 110 - 200 kilos per hectare have been obtained from natural stands. The amount of seed produced depends on whether moisture is plentiful and temperatures are cool during the period of blossoming and seed formation. Seed production may also be reduced by shading. In years of good growing conditions, the plant may produce 2 or 3 seed crops^[2]. The presence of seed heads and seed head densities may be increased by repeated annual burning^[2]. All members of this genus use the method of photosynthesis known as C4. This allows for the more effective capture of carbon dioxide and thus less water loss through transpiration since the stomata do not have to be open for transpiration. This is an advantage in the arid environments where these plants are usually found^[4].