"I love their famous Trebah Flans, yummy!" P. Atkinson, Truro
Its easy to assume winter to be a full-stop in the gardening year and to think most plants will be dormant until the warmer weather arrives in the spring. Luckily, that is not the case and I personally find it hugely reassuring that although the daylight hours are so short, there is a succession of wonderful plants flowering at Trebah throughout the bleaker months.
Many plants control when they flower to coincide with particular seasons by responding to the length of the day. This process is called photoperiodism and the photoperiod or day length, is the duration of light in a given 24-hour period.
The Sasanqua or autumn flowering Camellias are a prime example; they herald the progression of the seasons. The main Camellia season is from late winter to mid spring but the earlier Sasanquas bring colour to late autumn and early winter. It made me wonder why they choose this time of year to flower? Blooming may be timed so the flowers are more visible to the pollinators. In forests, such conditions exist when deciduous trees are leafless causing woodland flora to have many species that flower in winter and early spring.
At Trebah, the winter flowering plants include Sarcococca confusa (Christmas Box), Lonicera fragrantissima (Shrubby Honeysuckle), Hamamelis mollis (Witch Hazel), Mahonia x media Charity, Corylopsis multiflora, C. pauciflora, C.spicata and C.willmottiae. All of these have their origins in woodland habitats and the above may dictate their flowering period.
Bulbs too, have to flower before the forest floor is shaded by new leaves and Snowdrops even have evolved to penetrate hard snow covered ground by means of a tough leafy layer which covers the tip of each flowering stem and have a built-in anti-freeze.
Many Southern hemisphere plants such as Agapanthus from South Africa have adapted to our seasons but we had wrongly assumed that the Acacia mimosa and Acacia pravissima were flowering out of season (i.e. what they believe to be the Australian summertime). After a little research I discovered that the majority of Acacia species flower during the end of winter in Australia so they too have adapted to our seasons and are a wonderful addition as they light up the valley with their iridescent bright yellow flowers.