Cephalotaxus oliveri Seeds | Oliver’s Plum Yew
LATIN NAME: Cephalotaxus oliveri
COMMON NAME: Oliver’s Plum Yew
Plant Profile
The genus name is a description rather than a tribute: kephale for head and taxus for yew, because the male cones gather into small rounded heads instead of running along the shoot as they do in true yews. Cephalotaxus oliveri is an upright evergreen shrub or small tree, usually under five metres in cultivation, with stiff ascending branches and a narrow habit.
The leaves make the best field character. They are linear and leathery, set in two flat ranks along the shoot, each blade tapering to a soft point. Turn one over and you find two broad chalky-white bands of stomata divided by a narrow green midrib. The leaf bases twist so the blade lies flat to the light, giving the plant the combed look of a plum yew.
Male and female cones sit on separate plants. The female structure is a single ovule wrapped in a fleshy coat that swells as the seed ripens, turning green and then dull purple; birds eat the coat and carry the hard seed away. Inside sits one large seed with a stony coat, bitter with alkaloids and not a food.
Oliver’s plum yew is a plant of damp shade. It grows on ravine floors and stream banks in evergreen broad-leaved forest, on acid soils rich in leaf litter, and survives on cliff ledges under a humid canopy. Because it is slow and never forms stands, populations are small and widely separated, and the species is treated as rare.
Grow Oliver’s plum yew as an understorey evergreen rather than a specimen in the open. Set it on the north side of a wall or beneath high deciduous trees where it receives dappled light, and give it an acid soil with leaf mould worked in. The dark foliage holds a garden together in winter, and the plant tolerates root competition better than most evergreens do.
Science & Biotechnology
Cephalotaxus alkaloids have an unusual architecture: cephalotaxine supplies the framework, and a side chain esterified onto it produces the active forms, among them harringtonine, homoharringtonine and isoharringtonine. Chinese researchers isolated and tested these compounds against leukemias from the 1970s, and a semisynthetic derivative, omacetaxine mepesuccinate, was developed along the same line of work and approved in the United States in 2012 for chronic myeloid leukemia that has resisted other therapy.
The mechanism differs from that of the kinase inhibitors usually used in this disease. Harringtonine binds to the ribosome and blocks the elongation step of protein synthesis, so the cell stops making new proteins and dies. Because the target is the machinery of translation rather than one mutant enzyme, the compound acts independently of the mutations that cause resistance.
Since a mature plum yew holds only traces of harringtonine, laboratories have tried to grow the chemistry rather than harvest it. Callus and cell suspension cultures of Cephalotaxus have been established and screened for cephalotaxine alkaloids, and they also serve as a platform for mapping a pathway that is still not fully understood.
Uses & Benefits
Cephalotaxus is a genus of yew-like evergreens few gardeners could name, yet one of its alkaloids became an approved medicine for chronic myeloid leukemia. The compound is harringtonine, an ester of cephalotaxine, found in the plum yews by screening programmes that ran in China and the United States from the 1960s onward. Oliver’s plum yew belongs to the same chemical family.
Growing from Seed
Clean the seed as soon as the aril softens, rubbing the fleshy coat away in water and rinsing until the hard seed is bare, because the pulp moulds quickly in a closed container. Sow into a mix of two parts peat or ericaceous compost, one part perlite and one part sieved leaf mould, pressing each seed on edge about a centimetre under the surface. Use a deep pan, keep it cool and shaded, and cover it with grit and wire.
Water with rainwater where you can, since the plant dislikes lime, and keep the pan in a frame that stays humid but never wet enough to rot. Move the young plants on once they have made a sturdy rosette of leaves and a firm cone of new growth, potting them singly into deep pots of the same acid mix. Plant out once they stand about a hand high and have come through one winter outdoors, spacing them a metre apart in a group. Mulch with leaf mould each spring and shelter the foliage from winter sun, which scorches it faster than cold does.
Our Take
Plum yews are easier to keep than to find, and the genus rewards patience. Cephalotaxus fortunei is the larger, faster-growing relative and makes a fine background evergreen for the same shaded ground, while Cephalotaxus sinensis stays compact enough for a small garden. If the alkaloid story interests you, grow a yew beside them and compare; Taxus wallichiana holds a different set of alkaloids and a very different pharmacology.
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