The essential requirements for a budding trillium enthusiast are patience and/or a fat wallet; these plants are slow to grow from seed and to build into good clumps, and therefore expensive to buy. Also useful in helping to ensure success are shade, at least during the hottest part of the day, and a good rich soil containing plenty of organic matter, since trilliums are woodland plants. Like most plants that inhabit deciduous or mixed woodland in nature, trilliums make their growth and flower early in the year before the tree foliage cuts out the light. Having completed their growth and set their seed by midsummer, they soon die away leaving the slowly expanding perennial rhizome below ground to carry the plant forward into future years. And these may be many, for trilliums can be very long lived plants, I have a clump of the subject of this article in rude good health after two decades, and would expect it to outlive me by a good many years.
Propagation from seed is easy, provided it is sown fresh from the pod, but it is usually two seasons before anything is seen above ground and a further 2-4 years before the first flowers are enjoyed. Stale seed will germinate, or more accurately some of it will, but germination percentage is likely to be slow and the seedlings tend to lack the vigour of those grown from fresh seed. Mature clumps can be dug up and divided and this is best done when the plant starts into growth in early spring or after it has died down in early autumn. However, such divisions are often slow to establish and some may not make it even if given tender loving care. Another method of propagation, used by some in the trade, involves damaging or removing the shoot as it develops in spring. This will cause side buds on the rhizome, which would otherwise have remained dormant, to grow and subsequently form mini-rhizomes which can subsequently be removed from the main rhizome and grown on to flowering size, probably in 1-2 years.
So much for trilliums in general, now for some details of Trillium albidum. As can be seen from the close-up photograph, this is a sessile species, i.e. the flowers are stalkless, being borne directly on the ruff of leaves that subtends them. Other commonly grown sessile species include T. sessile itself, and the variable Trillium chloropetalum, with which T. albidum hybridises in the wild in the San Francisco Bay area of California to give a confusing melange of forms with flower colour varying from pure white, through white stained with pink or purple in the throat, to striped purple and white and pure dark purple or blood red. Two of the forms which probably represent the commonest colours in what is taken to be pure T. albidum are shown in the photographs.
As far as cultivation is concerned, my clumps receive a good mulch of garden compost or leafmould as soon as growth is underway in spring, sometimes supplemented by a handful of complete fertiliser, and are otherwise neglected. Ants carry the ripe seeds away, attracted by the sugary, viscid liquid surrounding them, so seedlings may appear at a considerable distance from the parent plant. In my garden self-seeding is common but not abundant, the seedlings usually appearing in clumps, which should be marked so that they are not inadvertently dug up or damaged when dormant.