Your gardener in Thornbury and the Severn Levels

Thornbury sits in an open bowl, closed in by higher ground to the south, east and north, and opening west and north-west towards the Severn estuary. The town averages around 43 metres above sea level, and the ground either side of it does not: the Levels below start at ten metres or less, and the ridge above climbs to about a hundred. Ninety metres of height inside a few miles of one town is the reason there is no single answer to what grows here.

Underneath the bowl and the ridgeline that frames it is Old Red Sandstone, with marl and clay taking over across the ground around them. That is a different proposition from the Cotswold limestone an hour north, and it wants a different approach.

The town — the old plots and the new estates

Thornbury's medieval core was laid out along two main streets and their crossing, under a charter of 1252, and the plots behind those streets are still long, narrow and enclosed — deep, often walled, and awkward to get a machine into. Then the population went from 12,063 to 14,496 between the 2011 and 2021 censuses, almost all of it on the eastern side. So within one town there are gardens that have been settled for centuries and gardens whose owners are still deciding what to put in them, and they need opposite things: one wants restraint, the other wants establishing. Upper and Lower Morton and Grovesend sit in the parish alongside.

Down on the Levels — Oldbury-on-Severn, Hill and Rockhampton

West and north-west the ground drops onto the Oldbury Levels, at or below ten metres, on alluvial gley soils that are seasonally waterlogged by definition. Gardens here sit wet through winter whatever you do, which rules out a good deal of the dry-and-gravelly planting that is fashionable elsewhere. The field boundaries are often rhines — drainage ditches — with hedges alongside, and a grass sea-wall embankment beyond, so a boundary here can be a watercourse rather than a fence. The standing work is old orchard trees and overgrown leylandii screens rather than fine borders — and leylandii is the one hedge where cutting it back hard does not grow back, so the plan matters before the saw comes out. Littleton-upon-Severn, Cowhill and the strung-out line of farms at Hill sit on the same flat.

The ridge villages — Alveston, Olveston and Tockington

South and south-west the Severn Ridges climb from the Levels' edge to about a hundred metres, and the villages sit on the lower slopes and scarp. Carboniferous limestone has been quarried around Olveston for centuries, and it shows in the boundaries: stone walls rather than hedges, low around the cottages and over two metres around the larger houses. That changes what the work is. A round here is beds, borders and edges rather than hedge lengths, and a high wall gives you deep dry shade on one side and a baked strip at its foot on the other. Rudgeway, Tockington and Elberton are the same ground.

East along the A38 — Tytherington and Milbury Heath

East of the A38 the land rises again onto the Tytherington ridge. Tytherington itself is marked by tall Pennant sandstone boundary walls beside its disused quarry workings, and Milbury Heath is a local high point looking west over the Severn Vale and north into the Vale of Berkeley. Exposed, and the walls are the local material again rather than the limestone of the villages to the south. Falfield sits north on the A38, in vale ground of its own.

If you're after a gardener in Thornbury, out on the Levels or up on the ridge, call 07443 797 834.

The garden is wet all winter and nothing I plant survives it. Is that fixable?

On the Levels, not really — and that is worth knowing rather than fighting. The ground there is alluvial gley, which is seasonally waterlogged by its nature, so the honest answer is to plant for it instead of draining against it. Plenty will grow in ground that sits wet; the gravel-and-Mediterranean look will not. I would rather tell you that than sell you a border that dies every February.

Looking for a gardener in Oldbury-on-Severn, or anywhere out on the flat?

Yes — the Levels villages are part of the same round as the town, at the same prices. The work out there tends to be old orchard trees and overgrown leylandii screens more than fine borders, and I am set up for both.

There's a two-metre stone wall down one side and nothing does well near it. Why?

Because it is two gardens, not one. The shaded side stays dry as well as dark — a wall keeps rain off the ground at its foot — and the sunny side gets the heat back off the stone on top of the sun it already had. Around Olveston and Tockington those tall limestone walls are the normal boundary, so it comes up a lot. Different planting each side is the fix, not more watering.