National Plant Collection of Trillium species and natural hybrids

Trillium grandiflorum ‘Flore Pleno’

The Royal Botanic Garden Edinburgh is home to several Plant Heritage National Plant Collections including Trillium species and natural hybrids. Trillium are found in the woodland garden at the Botanics and unlike our other National Plant Collections, which are also research collections, are fully on public display. The best time to see them is March through to May.

Historically Trillium has been placed in the Lily family, in its own family Trilliaceae and is currently in the Melanthiaceae a decision based on molecular relationships. Even though Trillium has caused some confusion in its family relationships they are relatively easy to identify to genus level with leaves, sepals & petals all in threes. There are two major divisions within the genus to divide the species, sessile and pedicilate plants. Sessile species are those where the flower emerges from the top of the stem at the same point as the leaves and pedicelate species that have a flower stalk so the flower sits clear of the leaves. Beyond that identification becomes more tricky unless you know where in the world the particular plant comes from.

Trillium luteum

The Botanics currently cultivate 69 accessions for Trillium, over 40% of which is of known wild origin. We have 29 species, varieties and hybrids as well as a few cultivated forms. Most of our wild plants are from the US (mostly from North Carolina and Georgia), with a few from Canada and two natural hybrids from Japan.

In 1817 Steven Elliott, an American botanist wrote in his A sketch of the botany of South Carolina and Georgia:

The genus is an interesting one. Under great simplicity and conformity of habit, 3 leaves at the summit of a stem, supporting one single solitary flower, it contains and conceals many species.

This is just some of the diversity at the Botanics…