Springtime colour is one of gardening’s greatest joys. Colourful bursts dispel the long darkness of winter with its depressing wetness and cold. Social research is clearly showing the physical and mental benefits obtained from the emergence in spring of bright garden colours linked with lengthening daylight. As with most gardening pleasures, this requires advanced financial outlay and an understanding of the rhythms of plant growth.
Planting bulbs such as daffodils, tulips and hyacinths in autumn is the necessary investment. In return, plant breeders now provide a huge array of colours, shapes, sizes and seasonal sequencing with bulbous plants.
Geoff Dixon: February Gold daffodils
Bulbs are large pieces of vegetative tissue which come pre-loaded with immature leaves and flowers, safely wrapped inside a dry coating of protective scales. Essentially, bulbs are large flower buds which are stimulated into growth by planting in warm, moist soil or compost. These conditions trigger the emergence of roots from the base of each bulb. Because bulbs are nascent plants, they require careful handling and are safest once planted.
Many bulbous species originate from higher altitude mountainous pastures and are naturally evolved for dealing with fluctuating periods of heat, cold and drought. Once safely planted at depths which should equal twice the length of each bulb, they will survive the freezing, thawing and fluctuating soil water- content delivered by winter weather.
Geoff Dixon: Bulb structure showing the flower bud embedded in the bulb
Warming soils of spring encourage growth and emergence of the leaves and flower buds contained within each bulb. Speed of emergence is governed by interaction between the genetic complement of bulbs and an interaction with their environment. Identifying and understanding the impact of this interaction formed the basis for Charles Darwin and Alfred Wallaces’ theory of natural selection. For springtime gardeners it is expressed in the multiplicity of bulbs on offer. Choosing a range of daffodil varieties for example, provides colourful gardens from February through to late May.
Geoff Dixon: Technique for planting bulbs using hand trowel and some sand for drainage under the bulb
Conserving the joys of spring pleasure over years can be achieved by naturalising bulbs. This means planting them in grass swards. This works effectively for daffodils, provided the foliage is allowed 8 to 10 weeks of uninterrupted growth and senescence after flowering. During this period, photosynthesis produces the chemical energy needed for replacement growth, which provides bulb multiplication and flower bud development for the following year. Tulips are much less easily naturalised in British gardens. This is because the leaves mature and senesce much more quickly after flowering, hence, less energy is produced, therefore, regrowth is less, and replacement flower buds are not formed.
For most gardeners the policy should be one of enjoying each springtime’s show and replacing bulbs with new ones every autumn for a relatively modest outlay.