This intriguing genus of shrubs is closely related to (and until recently, was included within) Hebe. It consists of five species from a group of plants that is commonly referred to as the 'whipcord hebes'. All five species are found in mountainous areas of the South Island, usually growing in exposed habitats. The only member of the genus to be commonly cultivated is the endangered Leonohebe cupressoides, a highly attractive and useful plant for cooler parts of New Zealand.

Leonohebe and Hebe are closely related to the predominantly northern hemisphere genus, Veronica. In fact, their members were classified as belonging within Veronica by early botanists working on the New Zealand flora. Some botanists advocate a return to the inclusion of all species of Hebe and its related genera (Chionohebe, Parahebe, Heliohebe and Leonohebe) into Veronica. However, this suggestion is best dealt with by the authors of the latest (and most authoritative work) on Hebe and Leonohebe¹ , who offer the opinion that lumping all species back into a very large, wide-ranging genus, Veronica, would "create a classification that is information-poor, obscuring obvious diversity and some clear relationships."

Leonohebe cupressoides

The appearance of plants is determined by many factors, including genetics, climate, geology and soils. It is an interesting phenomenon that, under the same conditions, completely unrelated plants can often take on a similar appearance. A good example of this is found in the 'whipcord hebes', which, with their tiny, closely appressed leaves, resemble montane conifers (such as the bog pine, Halocarpus bidwillii) more closely than their near relatives from other habitats.

This resemblance is aptly reflected in the species name of L. cupressoides, which means 'like a cypress'. Like other 'whipcord hebes', it has tiny scale-like leaves that are pressed close to the stem, with fairly unclear distinction between where the leaf begins and the stem ends. This is an adaptation to the desiccating winds of the dry mountainous habitats that it is native to.

In good years, it produces spectacular masses of light blue flowers, which seem slightly incongruous with its conifer-like appearance. The photographs within this profile are of specimens flowering in the wild at Lake Pukaki. There was an abundance of insects surrounding these plants, including a large number of what I assume to have been native hoverflies² and individuals of the butterfly species that is shown above, both of which would have been feeding on nectar.

The species is ranked as 'Nationally Endangered', due to a range of reasons, including the small size of the overall population and a lack of juvenile plants coming through. It grows in 'grey scrub' communities (a shrubland habitat type, which contains a predominance of small-leaved species) in a number of locations on the dry eastern side of the South Island. The Mackenzie Basin, where these photos were taken, is the New Zealand stronghold of L. cupressoides.

The adaptation of the leaves to desiccation by winds is slightly deceiving, as the species doesn't tolerate dry soil conditions as well as one might assume; a certain degree of moisture and fertility encourage the best growth. As within the wild, it prefers an open situation, growing at its best in association with other shrubs. Shrubs will eventually grow up to 1.5m high and spread as wide as 2m, although smaller dimensions are more usual in the garden (especially if plants are trimmed from time to time to maintain thick growth).

Footnotes

The quote given is from Bayly and Kellow's fine monograph on Hebe and Leonohebe, 'An Illustrated Guide to New Zealand Hebes' (2006, Te Papa Press, Wellington).
I did not check these closely at the time. However, bees are relatively scarce in alpine areas, and large native hoverflies are quite similar in appearance and flight habit to bees. They are common pollinators in alpine areas, where they hover above plants in flower.