Wednesday, 18 February 2009

Succulent groundcovers: Crassula species

I work with several indigenous Crassula species, including the more shrub-like form plants (and great, albeit different, bonsai material) C. ovata and C. arborescens. I personally enjoy the weird leaf form and spectacular flowers of C. perfoliata, and find that C. pellucida combines well with trailing Arctotis species.

However, it is to C. multicava and C. spathulata that I turn for tough Crassula groundcovers in the shade.

Crassula multicava is pictured here underneath Plectranthus ecklonii, during late winter (when the Plectranthus is in poor shape and fairly open). It spread itself, via seeding, down the very hostile retainer wall. It is a relatively moist area, and this Crassula does enjoy some degree of moisture. However, there's a gap as wide as the blade of a knife behind each of those retainer blocks - not much more than dust settles there. Once roots grow away, they should find a bit of soil in the blocks. The aspect is also tricky - north-facing; hot sun most of the day, most of summer; virtually no sun in winter (tall surrounding walls cut the sun). The picture was taken a year after planting the Crassula on top only. It is now 2 years since the picture, and the wall is densely covered - but nutrient deficiency is starting to show, as there's a yellowing of the leaves, particular where the sun is more persistent. I definitely prefer this Crassula in the shade.

Crassula spathulata has a very similar flower, for a much longer period, and at a different time than C. multicava. I do not rate the flower, though, finding that it gives an untidy appearance. This is a Crassula that I prefer for its leaves. It handles hot sun with less scorching, and looks better in dry locations than C.multicava. It has exceptionally beautiful texture and gloss, particularly in the shade. And that is my preferred location: dry shade.

No comments: