Star plants

Malus ‘Royalty’

Dicentra spectabilis

Euphorbia polychroma

Now we are well and truly into spring, in perhaps the most exciting month of the year, as the garden suddenly begins to look green and vibrant, and warmer days gladden the heart of every gardener.

Gardens are now awash with a bright spring display of flowers. All plants seem to start growing really fast this month, with April showers and warmer soil providing ideal growing conditions.

• Make an alpine trough – learn more here!
• Sow annual climbers and grasses
• Spray roses against black spot
• Sow greenhouse crops such as tomatoes
• Trim grey leaved shrubs to keep them bushy

April Weather Watch
On the whole, days are warming up but do beware of very cold nights with sharp frosts – these can damage fruit blossom. Clear, warm, balmy weather makes it very tempting to put young plants out now, but slightly tender plants still need daytime protection with cloches.

This little sink-style trough is easily made and will fit into a corner of the tiniest garden. At least half the price of shop-bought ones, it will look attractive for many months of the year.

(right) The finished feature, planted with a selection of spreading rock plants and a dwarf conifer

You will need:
Two cardboard boxes, the same shape but with one about 5cm (2in) bigger than the other all round
A “hypertufa’ mix of one part cement, 1 part sharp sand, and 2 parts seived peat-free compost: you need enough, roughly, to fill the smaller box, but overestimate to avoid running short
Wire netting and wirecutters
Wooden pegs or corks to create drainage holes
Bricks to support the mould
Plants used here:
Juniperus communis ‘Compressa’; Sedum spathulifolium ‘Cape Blanco’ and ‘Purpureum’; Lithodora diffusa ‘Heavenly Blue’; Thymus pulegioides ‘Aureus’

	1. Mix the hypertufa: here 2 shovelfulls each of cement and sand to 4 of seived compost
	2. Add water until you have quite a wet mix, about the consistency of porridge. Mix well.
	3. Cover the base of the larger box with a layer of the mix. Cut a sheet of netting to fit the base, snip out four or five holes (see above), and lay it over the hypertufa.
	4. Cut small lengths of roofing lath to make pegs. Insert them firmly through the mix; they will keep holes through the base clear to provide drainage for the trough.
	5. Spread another layer of hypertufa mix over the base to sandwich the netting. The more rigid “grille”-type netting is easier to use than chicken wire, as it stays flatter.
	6. Roughly pat down and smooth the base, brushing away any hypertufa that might impede removal of the peg later on.
	7. Place the smaller box inside the larger one. Cut four more oblongs of netting to fit the sides of the box, making them 2.5-5cm smaller each way. It is important that any sharp edges will be completely covered at the top. Set them in the gaps.
	8. Start to fill the sides with hypertufa mix, putting equal amounts each side of the netting.
	9. As you go, tamp the mix well down, again evenly on the inner and outer sides.
	10. Once the mould is filled, support it on both sides with bricks, as the hypertufa makes the cardboard damp. Leave it overnight.
	11. The next day, remove the bricks and peel away the cardboard, but don't try to move the trough. It needs at least a week to fully harden. Only then should you remove the cardboard from the base.
	12.Before the hypertufa sets completely, scrape away the corners to give a distressed look, using an old chisel. You can also scrape away any obvious lines left by the cardboard.
	13. Brush off the worst of the dust with a soft brush, and then go over the whole trough with a wire brush. This gives the trough the appearance of weathered stone.
	14. Leave to harden completely for about a week and then, using another peg, knock out the pegs to leave the drainage holes open.
	15. Set the trough up on bricks to ensure good drainage. Place crocks in the bottom to cover the drainage wholes, preventing them getting clogged with compost. Fill with an alpine compost mix of equal parts soil, peat-free compost and coarse grit.
	16. Plant up with plants of your choice. Spread grit or gravel over the surface to retain soil moisture and to prevent the plants being splashed with soil.