Parahebe catarractae Avalanche

The Parahebe catarractae 'Avalanche' is a lovely New Zealand shrubby speedwell, covered in a myriad of small white flowers throughout the summer. A fan of mild climates, this plant will thrive in a well-drained soil sheltered from cold winds, in full sun or partial shade. It also does well in a pot on your terrace, as it is undemanding.

The Parahebe, despite its complicated name, is a shrubby cousin of our well-known speedwells. Botanists even tend to group them together in the same genus, Veronica. It belongs in any case to the Plantaginaceae family, which includes most of the former members of the Scrophulariaceae, such as speedwells, plantains, snapdragons, and even foxgloves.

Parahebe catarractae is native to New Zealand: it can be found in gorges and on rain-swept rocks, with its roots well protected in cracks and crevices. It is a highly variable species, with some specimens adopting a prostrate and creeping habit, not exceeding 20 cm (8in), while others form a small bush. The Avalanche cultivar belongs to this second category: at maturity, it reaches about 30 cm (12in) in height and width, on lignified stems at the base. Its main characteristic is its abundant white flowering from June to September, with hundreds of small flowers typical of speedwells, with four petals and two protruding stamens. The dark green, evergreen leaves, except in extreme cold, are elongated and strongly dentate. The reddish-purple stems particularly highlight the flowering.

The New Zealand origin of the 'Avalanche' shrubby speedwell makes it suitable for not too cold regions: its hardiness does not exceed -10°C (14°F) in a protected location. Below -5°C (23°F), the evergreen foliage may disappear, but will grow back in spring. Place it against a west or southwest-facing wall, in bright partial shade or full sun, to protect it from cold winds from the north and east. While it can tolerate most garden soils, its hardiness is greatly enhanced by a healthy and well-drained soil, slightly sandy and not too heavy. Not very water-demanding, it can withstand temporary drought once well established. The only maintenance required is to remove any dead wood in early spring.

Perfect in a rock garden or in a pot, the 'Avalanche' Parahebe will be well accompanied by the New Zealand hair sedge, the Milk Chocolate sedge, the Karvinski fleabane, or even the Caucasian scabious, for a warm and colorful scene all summer long.