Holly berries are emblematic of Christmas. Decorative wreaths containing sprays of holly boughs, bright red with berries, or sprigs set on cakes and puddings help bring seasonal cheer.
Holly is a problem for horticulturists! Male and female flowers develop separately requiring cross-pollination before fertilised berries develop. Dutch nurserymen got around this by selecting a self-fertile variety ‘J. C Van Tol’ which sets copious berries. Adding further colour in the winter garden is the variety ‘Golden King’ producing mixtures of creamy-white and green foliage. Most hollies in Great Britain are Ilex aquifolium which is a native of Northern Europe and is still found wild in the Welsh Marches. It is a flexible and valuable garden evergreen, very suitable for hedges as they form tough, prickly, impenetrable barriers.
Why plants use considerable energy to produce brightly coloured fruits is a puzzle for botanists. Co-evolution is an explanation. Bright berries attract birds which eat them, digesting the flesh and excreting the seeds. Wide seed distribution accompanied by a package of manure helps spread these plants increasing their geographical range.
Which came first, bright berries or vectoring birds? A combination is the answer. Plants with brighter berries attracted more birds spreading their seed more widely. Brighter berries are more nutritious and hence those birds which ate them were stronger and better fitted for the rigours of winter. Garden residents such as blackbirds and thrushes now thrive and survive on such natural food. Migratory species such as fieldfares travel from Scandinavia, attracted particularly by other berried treasures such as Cotoneaster.
Fleshy fruits such as those of holly or Cotoneaster are examples of some of the last energy sinks formed in the gardening year.
They draw products of photosynthesis from the manufacturing centres in leaves and accumulate sugars plus nutrients drawn up from the soil via root systems. That provides a rich diet for birds.
While digestive acids in the vector’s gut starts degrading the hard shell which surrounds the seed at the centre of the berry. Botanically that term is a misnomer since true berries, such as gooseberry fruits contain several seeds. Holly has one seed contained within a hard case encased in flesh and should be a drupe! Not a term which fits well for Christmas carols, decorations or cards!
Merry Christmas and a Prosperous New Year.
Gooseberries- true berry