What is an English Lavender ?
There is some confusion in Australia as to what is an English Lavender. Originally ‘English Lavender’ referred to Lavandula angustifolia ssp angustifolia and its cultivars. There is a second sub-species which comes from the Pyrenees, called Lavandula angustifolia spp pyrenaica. There are few if any nurseries that have either of these in their wild form. There is a cultivated form of Lavandula angustifolia ssp angustifolia on the Australian market. If there was anyone selling the other sub species there wqould be few, if any, people who could tell the two apart, even when in flower.
L. angustifolia is part of the group known as Spike or Spica Lavenders (Lavandula section lavandula), due to the flowers being borne at the end of a spike or peduncle, which can be up to 50cm long. The other two species are L. lanata and L. latifolia. It has the following synonyms: L. officionalis, L. vera & L. spica. Lavandula lanata, is called The Woolly Lavender due to its woolly appearance and silvery foliage, it is easily distinguished from the English Lavenders.
The third member of the group, L. latifolia is known as The Spike Lavender. The mature plants are quite different from those of L. angustifolia. This plant is again, not very common in commercial nurseries. It generally flowers in late summer / early autumn. The peduncles are up to half a meter long and often branched into three. The flowrs are 5-15 cm long, and are usually interrupted and shaped like a rat’s tail. The bush is only small (up to 60cm), and both the folage and flowers have a strong camphor scent.
L. angustifolia in contrast usually flowers in late spring / early summer. It is the first of the Spike Lavenders to flower. The flowers are shorter, squatter and rarely interrupted. The peduncles are generally shorter without any branching. The flowers are usually deeper in color and along with the foliage have a much sweeter aroma, with little or no camphor. It is a bigger plant and can be up to 0.8 metre without flowers.
Between the two are the Lavandins (Lavandula x intermedia), which are hybrids of L. angustifolia and L. latifolia, and commence flowering between January and March. Many of the named hybrids are are now being sold in Australian nurseries. They have characteristics from both parents. Most of them are more floriferous than either parent and have aromas that have some camphor but not as much L. latifolia.
It is the hybrid Lavandula x intermedia and the true species lavandula angustifolia that are hard to tell apart. The nomenclature problems arose because many Australian nurseries a) didn’t know of the hybrid and b) grew L. angustifolia and L. latifolia from seed. Seed raised plants are extremely variable and may often be of mixed parentage. With the variation in the hybrids and the variation within the species and the variation within climatic regions it wasn’t long before the whole lot beame and identiification nightmare.
Nurseries should grow all their varieties by cutting to ensure that all plants are true to type. A classic example of seed plants becoming an issue is the variety ‘Hidcote’. Originally this plant was selected and brought back from France in the 1920s to Hidcote Manor. During the forties this was then put into the trade Thomas Carlile of Loddon Nurseriers. It is a compact form with very dark flowers. There is a cultivar in the Australian market called Hidcote Carlile and it is cutting grown from plants that are direct descendants from the original bushes.
Most Australian forms of Lavandula angustifolia ‘Hidcote’ are eithr grown by seed or are cuttings from plants that come from seed. The Australian Hiocote is extremely variable and should not be classed as true Hidcote. The true form has one several medals by the Royal Horticultural Society.
The whole issue of seed raised plants becomes an even bigger problem when plants are grown commercially. In general people would not contemplate a seed raised lemon, apple or cherry and lavender is no different. The yield from seed raised plants is far too variable for true commercial oil production.
Back to the differences; short tight flowers on compact spring flowering bushes and you would normally have a form of Lavandula nagustifolia.. If the plant is more open, the flowers are more spread out on the plant and the flowers are elongated and you have L. intermedia.
The hybrid is the better looking bush but the species produces the best oil.