How to Care for a Bonsai Tree in Spring
Early spring is a period of intense change for plants, it is a transition from the challenges of the winter weather to the much milder temperatures of spring. This can potentially be a very hazardous time of the year, when there is still a risk of severe frost. Particularly at the beginning of the month, at a time when the young buds may have started to grow after a mild winter. Watch out for any serious changes in the weather, bearing in mind that winter is hardly out of the way yet.
Watering is a skilled operation at this time of year, as budding plants require a lot of water, but this puts their root balls at risk from frost if the temperature drops sharply. During this period, it is well worth protecting trees at night and when the weather is overcast and then placing them in a more exposed spot when the weather is fine and mild. Anyway, watering should be limited, as over-watering when it is warmer will lead to excessive budding (bad for bonsai). which then calls for early pinching out. Do not use fertilizer until you are sure the plant has started its growing period. As this would cause the tree to grow too quickly, with the same effects as excessive watering.
Most trees should be pruned for shape before they start growing (usually during the first three weeks of early spring). It is not a good time to do wiring, as the sap on deciduous trees should be flowing freely before they are wired.
If you have some shelter (a cold frame or even better a greenhouse), early spring is the ideal time for seed-raising. In good conditions, the seeds will take a few weeks to come up, taking advantage of the milder mid- and late spring weather to germinate and grow. For all early flowering plants, such as jasmine, now is the time to cut away all faded blooms. Any of these which are left on the tree could encourage fungal disease. It is also a good time for grafting.
This is a period of intense growth, (particularly in northern regions), though there is still a risk of frost, especially during the earlier part of this period. However, a drop in temperature will no longer freeze theball through – but the more tender outdoor trees must still be protected.
The earliest weeks of mid-spring are considered to be the best time for transplanting conifers, though it is usually too late for deciduous kinds, which are by then in full growth. It is also an excellent time for grafting, particularly for cleft grafting conifers.
Spring-blooming shrubs are at their best, ablaze with colourful. As in early spring be sure to cut away all dead blooms whenever necessary. As soon as the shrubs have lost all their flowers, they can be pruned to shape. Do not delay , which must be carried out before new buds appear, as blooms are always borne on the previous year’s wood. Any delay in pruning will stop them blooming the next year.
If the season is particularly mild, try to limit over-rapid growth by restricting watering, the use of fertilizers, and by pinching out if necessary. Late in mid-spring is also a good time to lift outdoor conifers. It is also time to start transplanting in northern regions, provided the soil has thawed out completely.
This is a good time to repot conifers (before they start into growth) and also to prune their roots.
Mid-spring, like early spring, is a good time for seed-raising. If the seeds are sown in pots in a cold frame, ensure that they are exposed to the air as soon as they begin to sprout, but to shade them from strong sunshine. Seeds and seedlings should be watered moderately, as over-watering in a confined area could set off damping-off disease which quickly kills the young plants.
While late spring is certainly a peak period for flowering shrubs, it is the season when bonsai spring back to life with the start of the summer (although there is the risk of a late frost).
Some kinds with delicate leaves (maples, for instance) must be protected against scorching sun, which can easily damage the young shoots.
Be more attentive to watering, in view of the rising temperatures and increased sunshine. This does not mean drowning the plants at the first sign of the soil becoming dry. Excessive watering only leads to over-rapid growth of shoots and larger leaves or needles. Moderate watering will produce smaller leaves and shorter needles.
The same applies to fertilizers. Over-use of fertilizers causes too much growth too rapidly. Deciduous trees require more care than conifers. For a good stimulant, liquid fertilizers are best.
The development of new growth makes late spring the first suitable time for pinching shoots and clipping leaves. The buds of conifers in particular should be reduced, while the leaves of deciduous kinds can be clipped until mid-summer.
Special care must be taken of flowering shrubs of the heather family, like rhododendrons and azaleas, as their dead flowers must be removed. This is a delicate operation which must be carried out when the seeds start to form and not when the blooms start to wither.
Care must be taken not to cut the young shoots which are beginning to grow at the base of the pistil and which will eventually carry the next year’s flowers. Later, these shoots’ growth will have to be kept in check to make sure they do not spoil the shape of the tree. A choice will have to be made between a profusion of flowers and the shape of the bonsai. Measured use of fertilizers will help these plants as they start to make new growth.