It is a small tree, often found growing in hedgerows or at the edge of woods. The Plymouth Pear is considered to be either a sub-species of Pyrus pyraster (European Wild Pear) or a distinct species.
Pyrus cordata is a deciduous shrub or small tree growing up to 10 meters in height. It is hardy to zone 8[clarification needed] and is not frost tender, but its ability to bear fruit and thus seed is dependent upon favorable weather conditions. It is in flower from Apr to May. The flowers are hermaphrodite and are pollinated by Insects. The trees have pale cream blossom with some pink. The smell of the blossom has however been described as a faint but disgusting smell compared to rotting scampi, soiled sheets or wet carpets. The odour attracts mainly flies including some more often drawn to decaying plant matter such as Bibio marci.
Pyrus cordata prefers light (sandy), medium (loamy) and heavy (clay) soils, requires well-drained soil and can grow in heavy clay soil. It prefers acid, neutral and alkaline soils. It can grow in semi-shade (light woodland) but prefers full sun and often grows in hedgerows and at the edges of woodlands. It requires moist soil and can tolerate drought. It can also tolerate atmospheric pollution. It is common in Brittany, Northern Portugal and Galicia where it occurs at woodland margins on acid soils.
The Plymouth Pear has an Atlantic distribution and is found in Western Europe in France (notably in Brittany), Portugal and Galicia and with a small presence in England where it is now believed to be an archaeophyte.
It occurs in thickets and open woods with cool-temperate climates, in lowlands and hills. Not much about its requirements in England are known, but conservationists are looking at how it behaves in Brittany to get an idea about its requirements.
English & Cornish population
The species receives its English name from the area it was originally found growing in; Plymouth in 1871 by a local naturalist; T. R. Archer Briggs. In England the species is very rare and is confined to two areas – Plymouth and Truro.
The genetic diversity of the species in England is very low with the two widely scattered populations being genetically identical which suggests that one of the populations was established from clone material taken from the other (suckers or cuttings).
However this lack of genetic diversity is a threat to the population because most of the seeds are infertile, but efforts are being made to conserve the population by controlled breeding of trees in botanical gardens and by attempting to induce genetic mutations and variation in cultivated specimens. Genetic material from Europe is being avoided, so no trees are being introduced from the mainland European population. The conservation of the species involves attempting to increase the genetic diversity and so it is hoped that some mutations will take place with the cultivated stock which it is hoped will allow them to breed more successfully (Pears are self-sterile, so clones cannot breed easily with other clones). The species suffers from low seed fertility caused by the inbreeding of the two populations in England and conservation efforts are attempting to combat this. The two populations are also threatened by the use of the landscape but they are being preserved in protected areas in their range.
- Edward Milner – Trees of Britain and Ireland, page 115
- Jackson, 1995
- Pyrus cordata at Arkive
- Kew Gardens page about Pyrus cordata
- Pyrus cordata datasheet (PDF)