Rain shadow planting: set roots 45 cm from the wall

You have watered the lawn, and the soil against the house wall is still pale. The plant is meant to climb there, so the hole ends up in the driest strip in the bed. Rain shadow planting puts the root ball where the rain lands, about 45 cm out from a solid wall, and trains the stems back to the support. We used the Royal Horticultural Society notes on how to plant a climber and on training at planting, the BBC Gardeners' World climber guide, and the society note on brown leaves on woody plants. This is not a garden trial. A qualifying purchase through our links can earn a commission at no extra cost to you.

The plants sit on the climbing rose comparison. In that October 2026 set there is no top pick. The best value is a Blue Magic Design white bare-root climbing rose at about £21.65, with 4.1 from 13 ratings, and the seller states a mature height of 90–120 cm. That cane still needs the 45 cm gap and water in the first growing season. The price is not a measure of how long a plant can sit in a rain shadow.

In short

A solid wall or a close-board fence throws rain outwards, so the base stays dry when the open bed is wet. Set the root ball about 45 cm (18 in) out. That is the Royal Horticultural Society figure, and BBC Gardeners' World says at least 30 cm, preferably 45 cm. Water through the first growing season, and lay mulch on the soil, clear of the stem.

The dry strip at the base

Rain shadow planting names the dry band at the foot of a wall, a house, or a solid fence. The surface catches the rain and sheds it further into the bed, so a shrub planted in that band gets less water than one a step further out. After a shower the brick is often dark, and the soil against the footing is still dusty. Wet masonry is not moist compost around the roots.

The tips can stay green for a while, because the nursery had already grown them, while the roots sit in dry soil. A south face adds heat. A north wall does not cancel the loss of rain. Shade decides the flowers. It does not water the roots. Scrape a few centimetres down at the base, then again about 45 cm out. If the inner soil crumbles and the outer soil holds together, you have found the shadow. A downpipe can soak one corner and leave the rest dry, so do not sample only the puddle.

A deep eaves is the limit of the usual figure. A wide roof can push the dry band past 45 cm. If the soil is still dusty at that mark, move out until you reach ground the rain has wetted, and train the stems back. A gutter that misses the bed can flood one metre and starve the next. Read your wall, then dig.

The 45 cm hole

How far from a wall to plant decides the rest of the summer. The Royal Horticultural Society planting guidance is about 45 cm (18 in). BBC Gardeners' World asks for at least 30 cm and prefers 45 cm. For planting climbers against a wall in Britain, use 45 cm from the face of the masonry or the solid fence. Thirty centimetres is the short end. It leaves more root in the dry strip, so use it only when a path, a drain, or a step will not allow the longer gap.

Dig at that mark, and dig wider than the pot. A slot against the bricks puts the roots back in the shadow. Soak the container, then set the compost level with the surrounding soil, unless the label states a different depth. A climbing rose is the usual exception, because the union has its own depth. Take that figure from the climbing rose comparison. The gap is still about 45 cm. Do not sink the rose into the bricks to seat the union. Run a cane back to the wires or trellis and tie the stems before you finish. Loose stems can rock the new root ball. If the support is missing, fit it before you dig.

Spring and autumn are the easier planting times in the UK. Plant less hardy plants in spring. A hardy shrub or climber can go in during autumn. Do not plant into frozen or waterlogged ground. Midsummer planting can still succeed at 45 cm if you water until autumn. Mark the distance from the face the rain hits. If a concrete footing juts into the bed, do not sit the root ball on it. Those steps sit with the notes on the how to plant a climbing rose page.

A solid fence and an open support

A solid fence makes the same dry strip. Close-board timber, sleepers, and a gravel board block rain the way brick does, so the distance stays about 45 cm. An open trellis or a gappy picket lets more rain through, and you can come a little nearer if the soil is moist after a shower. If a kickboard keeps the base dry, use the full 45 cm. Leaves up the panel do not water the roots. Feel the soil after rain before you treat the fence as open.

Water and mulch in year one

The gap lets rain reach the roots. It does not make a new plant drought-proof. Watering new shrubs and a new climber continues through the first growing season, which is the companion to the Royal Horticultural Society distance. A 9 cm pot has less root than a plant already out in the border, and it dries sooner. Dry soil at the base of a wall still appears in a rainless fortnight in May, including just beyond 45 cm, and faster on a warm south face.

Feel a few centimetres down before you water. If that depth is dry, water slowly at the root ball until it is moist. If it is wet, leave it. A splash on the surface wets mulch and misses the roots. You can keep a too-close plant alive only while you never miss a week. The further hole still catches a shower when you are away. Put mulch on the soil over the root zone after watering, and keep it off the stem. A collar on the bark can rot the stem. Do not bury the stem for winter. Check after rain as well, because a sharp shower can run off baked ground.

Brown leaves on the lower stems

Brown lower leaves are the warning to check first when a climber stands at a wall. The Royal Horticultural Society note on brown leaves on woody plants links that lower-leaf pattern with dryness. Scrape the soil at the root ball. If it is dusty, and the browning starts at the bottom while the tips still grow, the roots have been short of water. Water slowly there, and put the next plant about 45 cm out. One tired nursery leaf after planting is ordinary. A run of brown leaves up the lower stem after a dry spell is the rain shadow.

If the root ball is moist and the lower leaves are still brown, stop adding water. A buried stem, a hole that puddles on clay, or the wrong light can brown leaves as well. This page stops at the hand test and the 45 cm. It does not name a disease. The usual loss is a hole in the dry strip and a splash on the way past. Lift the plant in its first autumn, out to about 45 cm, when it is dormant, and water it as a new planting. If the roots have already reached moister ground, water the outer edge of that spread and leave the plant where it is.

When the plant was the wrong one

A correct hole will not fix a wrong plant. Rain shadow planting will not make a sun-lover flower on a dark wall, and it will not make a wet-ground plant happy in a bed that drains in an hour. If the label photograph is a south wall and your fence is shaded most of the day, change the plant before you argue about centimetres. The replacement still needs the gap. Dry roots and the wrong light can fail together, and they are different repairs. Water at 45 cm can keep a mismatched climber alive. It will not supply the flower the pot was sold on.

A climbing rose uses the same gap, then its own depth. Set it about 45 cm out and take the union depth from the climbing rose comparison. Do not plant tighter to the wall to bury the union. The union is a vertical measurement. The rain shadow is a horizontal one. A twiner on a bare panel stalls however often you water. Fit wires or trellis on planting day. A crushed or dead plant is a delivery problem, and a leaking gutter is the opposite of a rain shadow. Feel the soil before you copy 45 cm from a dry wall onto a boggy corner.

Common questions

The practical questions are what a rain shadow is, how far out to plant, whether a solid fence counts, whether extra water can replace the gap, when planting is easier in the UK, why the lower leaves brown, whether a climbing rose is included, and where the mulch goes.