Davidia have become the best known of all hardy exotic trees and are commonly grown in parks, parkland and woodland as freestanding specimen trees. Ernest Wilson considered it to be ‘the most interesting and beautiful of all trees of north temperate flora’ and likened its huge white bracts to ‘huge butterflies hovering among the trees’.
Around 100 years ago gardens started a competition to grow the largest davidia in the UK. Some cheated by planting three trees together in the same pit and Caerhays was no exception. The end result was a 60ft tall tree with a huge spreading bowl and a canopy of at least as much with branches touching the ground. Quite who won is unknown but the inevitable eventually occurred with the Caerhays tree when the three parts split asunder. A 40ft single ‘honest’ replacement tree now grows in the same place.
Davidia involucrata produces its enormous white flower bracts in March or April. The centre of the flower has a small male flower with red-purple anthers and a single rounded ovary. Each flower is surrounded by a pair of bracts of unequal size and length.
The leaves are up to 15in long with heart shaped bases, mid green above and softly hairy beneath. The seeds or fruits are spherical and about an inch across held on a long hanging stalk. The seeds are green turning brown when ripe.
The seeds are notoriously difficult to germinate and take two years to do so in a large pot in a cool vermin free position. The trick is to lightly mow over the seeds on the ground with a rotary lawnmower. This scarifies the thick ridged fruit and we have found much more success in germination as a result.
Davidias are slow to flower for the first time as they grow exponentially when young and see no need to do so. Patience is needed and you may need to wait 10 years for a result. The question is frequently asked of us as to what can be done to speed the process up. The answer, regrettably, is nothing except to let nature take its course.
Sometimes young davidias develop two or more leading shoots. This is undesirable as it may well cause your plant to split in half in maturity. Judicious pruning in winter to leave just one leader is required.