So many misties in March, So many frosties in May.
A dry March and a dry May portend a wholesome summer if there be a showery April in between.
When it thunders in March one may say ‘Alas’. March comes in like a lion, goes out like a lamb.
As many mists as ye have in March, so many frosts in July.
A peck of March dust is worth a king’s ransom.

We disagree with those who describe March as the starting month of the gardening year. It is we know customary with many owners to leave their gardens alone through the winter and think about making a fresh start when they get a few sunny, spring like days in March. They are not keenly enthusiastic horticulturalists who adopt that custom. Nevertheless, it is perfectly true that March is quite one of the busiest and most important of the twelve divisions of the year. Subject, still, to the absence of bad patches of wintry weather much seed may be sown in both the vegetable and flower garden, and under glass the sowings may cover a wide range of subjects.

Any planting of deciduous trees, shrubs, fruits and roses still remaining to be done should be completed as soon as possible to give the roots a chance to get a grip of the soil before heat and drought may punish them. This is a good month for planting delphiniums and lupins, safer than autumn if the soil is heavy and retentive of water, and quite late enough in spring for practically any district.

Spring flowers become increasingly plentiful as March travels its course. Early daffodils make splashes of gold and blue squills provide a vivid contrast. In the rock garden there are gems of rare beauty, every day seems to bring something afresh to view. A little protection for specially choice fragile blossoms may be necessary, for bleak winds bruise and batter delicate petals.

These notes are as relevant today as they were when they first appeared in 1938. At the time of writing I do not know if the snow of December and early January returned to ruin our plans again but it certainly had a great effect in terms of delaying the spreading of compost and winter digging. Mercifully a covering of snow affords plants protection from frost so the damage is not as bad as very low temperatures with no snow. The weight of snow does cause some damage but most plants will quickly recover. The main adverse weather features of March are wind and frost and we can, with a little thought and some hard work, mitigate the effect of both. As far as frost is concerned frost frequencies increase the further you are from the coast, the further north you are and are more prevalent on high ground although this last factor may be contradicted by local considerations. Frost will flow downhill and accumulate in hollows – if you stand at the highest point in your garden and imagine that you are pouring a large amount of water onto the garden, try to imagine the course of the water down the garden carefully noting points where it will accumulate. The first thing this will tell you is where not to put plants that are not ‘frost hardy’ secondly it will indicate areas that you may be able to improve in terms of encouraging the cold air to flow through the garden.

If the garden lies on a flat plain, very little can be done as cold air cannot ‘drain over level ground. One answer is to create almost air tight walls surrounding areas of the garden – the air inside the walls will only cool by radiation on the spot and not by the invasion of cold air flowing into the garden. If the garden lies on a slope the first thing to check is whether it lies in the track of pronounced air flow. If this is so steps can be taken to divert this air flow. Ideally the wall or hedge lying at the highest part of the garden(up-slope boundary) should not lie along the contour as it will form a frost pocket on the upper side (which may not necessarily affect your garden) it should preferably lie at an angle across the slope. The cold air will then be diverted down the lower side of the garden. If the boundary hedge or wall is in the shape of an inverted ‘V’ the cold air will be split to flow down both sides. If this up-slope boundary must, by force of circumstances, lie along the contour line, then we need to consider whether we should make the boundary as high and as impenetrable as possible, or whether it should be an open boundary to allow air to pass through. If the slope is south facing a tall dense boundary will cause no shading and we have nothing to lose (as far as our own garden is concerned) in allowing a frost pocket to form on the up-side of the boundary. A garden on a north facing it is a different matter – a south facing slope is an ‘early’ slope in that fruit blossom, for example, tends to occur when there is still a big chance of frost. On the north facing slope the blossom period is several days later and by then the danger of frost may have diminished.

Nevertheless to diminish the risk even further we must still take the down-slope cold air flow into consideration – a tall boundary at what is now the south end of the garden will create a large area of shade. Under these circumstances it is better to have an open ‘up-slope boundary’ and to let the cold air travel through the garden without giving it the chance to collect in a frost pocket. Within the garden itself we must avoid any ‘cross barriers’ which would encourage the pooling of air. They should be planned to guide clod air flow to the sides of the garden and away from the sites planned for tender plants. Gaps in hedges or walls may let cold air escape but also cause unwelcome draughts. If we are protected on the up-slope boundary, risks can be taken in internal planning, but if cold air is unavoidable, then internal planning becomes more important. The old style landscape garden combined beauty with practicality when one of the stately houses of old England looked over a gentle down slope to a distant vista or ornamental lake. This type of garden often incorporated a ha-ha or sunken hedge which was not visible from the terrace of the house but was animal proof and did not cause anything worse than a very local hold-up to the cold airflow. If the garden is situated at the bottom of a slope which looks snug and sheltered and is warm on a calm July day, then little can be done to reduce the risk of frost.

A village in a valley or a cottage in a dell does not enjoy a perfect climate – it has an overdose of fogs and mists and the gardens are often only fit for the cultivation of frost hardy vegetable and flowers. Our ancestors often realised this and in several country villages farmhouses have been built a little way up the sides of the valley, just above the level to which fog often crept. By avoiding the fogs, the old farmers also avoided frosts. If you look round your garden and find that a treasured plant, tree or bush is not doing as well as expected consider the above with a view to providing additional protection or as a last resort move the plant, tree or bush. As far as March winds are concerned similar steps to those outlined above for frost are valid to a large extent. The biggest danger is ‘gusty’ wind where the variations in strength and direction are greater than normal. A gusty wind of moderate force might cause more damage than a stronger but steadier wind. When considering the effect of an obstacle or barrier we must be aware of the resultant gustiness as well as the mean wind conditions. The more abruptly a wind flow is interrupted the greater the probability of severe gusts. The wind must therefore be filtered into a ‘tame’ condition, not violently arrested. A solid barrier may halt the horizontal movement of the wind near the surface of the ground but may also bring about certain undesirable features. In describing the effect of a barrier on windflow it is convenient to consider the distance from the barrier in terms of barrier height. Up- wind of a solid barrier, the wind rises and flows over the top of the barrier, leaving a narrow zone of relatively low wind speed on the down-wind side. The length of this protected zone does not exceed one or two barrier heights. The partly protected zone is of appreciably greater length – up to about ten barrier heights. The rate of recovery of wind is however quite rapid and in the process fairly gusty conditions arise. The conclusion appears to be that solid barriers are not ideal boundaries for a normal garden.

A slightly different t of affairs occurs if the barrier is semi-permeable, such as a hedge or a paling fence. Here the wind will be filtered through the barrier and treated far more gently than is the case with a solid barrier. The drop in wind speed is less than before but this drop is maintained over far greater distances and the relatively slow ‘speed recovery’ rate is not accompanied by violent gusts. With a reasonably thick hedge or a fence with 50% solidity, the wind is cut to about 25% of its outside strength at about five ‘hedge heights’ down wind. The drop in speed is quite considerable up to about three or four times this distance. Up-wind of the barrier the partly protected area has a depth of about five ‘hedge heights’.

Hopefully the above will help in understanding why we have problems with some of the things we grow and perhaps lead to an increase in performance either in crop or flowering performance even if it means moving things around or improving comfort.