Planting for a dry summer: soil, water, shade
A garden that comes through a rainless summer is decided long before the rain stops. The work is mostly in the ground: deep, open soil that holds winter moisture, a mulch that keeps it there, and plants chosen for the conditions rather than against them. Watering then becomes a matter of timing and restraint, not of volume. Readers who want to see how the same problem is handled where summers are reliably dry, and where village planting has been refined over decades, will find the question treated at length in Rancho Santa Fe Living, a magazine about houses, gardens and country life in that part of California.
The editors of Notes from W4 –
What does dry soil actually need before planting?
Most dry ground fails for two reasons: it is compacted, and it is bare. Compacted soil sheds water rather than absorbing it, so a heavy watering runs off the surface and reaches very little root. The remedy is mechanical and unglamorous. Fork the top 20 to 25 cm without turning it over, working in garden compost or well-rotted manure along the way. On heavy clay, add grit as well; on thin sandy ground, add organic matter in quantity, because sand drains too fast to hold anything.
Plant in autumn where you can. Soil is still warm, rain is more reliable, and roots establish before the first dry spell rather than during it. A plant put in during July spends its first weeks surviving, not growing.
Mulch immediately after planting, 5 to 8 cm of bark, leafmould or composted green waste, kept clear of stems. This single step does more for a dry summer than any amount of extra watering, because it cuts evaporation from the soil surface and keeps the root zone cooler.
How much should you water, and when?
Less than most people do, and less often. A light daily sprinkle encourages shallow roots, which is the opposite of what a dry summer requires. Aim instead for a thorough soak every seven to ten days on established plants, enough to reach 15 to 20 cm down. A finger pushed into the soil tells you more than a glance at the surface.
Water in the early morning or late evening, never at midday. Water the ground, not the leaves. Newly planted shrubs and trees need more attention in their first two seasons, then progressively less as they root outward.
Containers are a separate case and will need daily attention in hot weather. Group them so they shade one another, and stand them in saucers to catch what drains through.
A rain butt or two, filled over winter, covers a surprising amount of summer demand if it is used where it counts: on new plantings and on the vegetables, not on established shrubs that can manage alone.
Where does shade come from when there are no trees?
Shade does not have to be mature. A trellis, a fence, a shed wall or a line of tall annuals will all cast useful shadow, and they can be moved or replaced as the garden changes. In a small plot, the north side of a hedge or a building is often the most forgiving ground in the garden: slower to dry, slower to bake.
Plant in layers. A tall shrub or a small tree gives afternoon shade to lower planting, which in turn covers the soil surface. This is the structure that dry-climate gardens rely on, and it works at any scale. Even a single fig, olive or hazel, kept pruned to a manageable size, changes the conditions beneath it within three or four years.
If you are planting a hedge, choose species that tolerate dry ground once established: hornbeam, field maple, yew, or a mixed native mix. Water them well through the first two summers, then let them find their own level.
Can a village garden hold together without a permanent lawn?
Yes, and in a dry summer it often looks better for it. A lawn is the thirstiest element in most small gardens, and one that browns off in July takes the whole plot down with it. Replacing part or all of it with gravel, bark, or a low planting of drought-tolerant perennials removes the problem at source.
Gravel over a weed-suppressing membrane suits lavender, thyme, rosemary, sedum, cistus and ornamental grasses. It needs little water once established, and it reads as deliberate rather than neglected. Where a green surface is wanted underfoot, a mown path of chamomile or creeping thyme is an option, though it will not take heavy traffic.
A small area of lawn can be kept if it earns its place: a bench, a drying line, a place for children. Keep it small, cut it less often in dry weather, and let it go brown without alarm. It will green up again after rain.
What holds a village garden together is not the lawn but the structure: hedges, paths, a tree, a seat, a few pots. Those elements carry the plot through a dry spell, and they are the same elements that make it legible from the lane.
Which plants earn their place in dry ground?
Choose plants with grey or silver foliage, small leaves, or aromatic oils: these are the visible signs of drought adaptation. Good performers include lavender, rosemary, sage, thyme, oregano, cistus, santolina, euphorbia, sedum, verbena, gaura and most ornamental grasses. Among shrubs, choisya, ceanothus, buddleja and phlomis manage well once established.
For height, consider olive, bay, fig or a small pine, all of which tolerate dry summers provided they are watered through establishment. For autumn interest, add sedum and asters, which flower late and ask little.
Avoid plants that need constant moisture: hydrangeas, hostas, most ferns and anything described as bog-loving. They can be grown, but only where shade and water are reliable, and they should not be the backbone of the planting.
Group plants by water need rather than by colour or height. A bed of thirsty plants next to a bed of dry ones will always be watered wrongly for one half or the other.
What does the first summer ask of you?
Patience, mostly, and a willingness to lose a few plants. The first summer after planting is the test, and it is reasonable to water new stock regularly through it. After that, the garden should be doing more of the work than you are.
Keep a note of what survives and what does not. In a dry year, the failures tell you more than the successes: they mark the spots where the soil is thin, the shade is wrong, or the drainage is poor. Those are the places to change the ground, not to replant the same thing.
By the third summer, a garden planted for dry conditions should need watering only in the longest spells. That is the point at which it stops being a struggle and starts being a place.
Dry summers and long winters are two readings of the same ground, so the notes on gardening where winter is long sit beside the sowing described in the meadow page.
The watering intervals quoted here follow the RHS advice on watering plants wisely.