Understanding Garden Plants -Alpine And Rock Garden

Question 1

Rock garden - summer

Answer 1

Thymus silver queen 
Sempervivum red Ace 
Saxifraga 'myriad'
Helianthus nummularium 
Dianthus alpinus

Question 2

Rock garden - spring

Answer 2

Sedum acre
Pulsatilla vulgaris
Euphorbia myrsinites

Question 3

Characteristics of true alpine

Answer 3

Low growing
Often very deep root systems
Adaptation of leaves - small/hairy/succulent/silvery
Alpines prefer acidic or peaty soil and dislike fertiliser.
They flower early, usually right after a thaw in the snow, and reproduce quickly.

Question 4

Other plants suitable for rockery

Answer 4

Dwarf conifers and bulbs

Question 5

Soil requirements for alpine plants/rockery

Answer 5

Free draining
Low nutrient content
Free from weeds/pest/disease

Question 6

Preparation of an area for rockery

Answer 6

Mark out the area using marker spray or with dry pale sand poured from a bottle.
Ensure that the area is weed-free
Build a base 15cm deep of rubble/broken bricks/stone
Spread a layer of inverted turves over this or a polythene sheet with holes or permeable landscape fabric
Select large stones to act as ‘keystones’. Position the biggest first and place the remaining ones so it looks natural.
Use a spade to dig out hollows to set the stone into.
Support big stones with smaller stones or bricks underneath.
Aim for a naturalistic look when setting the rock in place. The rocks should tilt backwards
Use top soil with added grit for the top layer of the rock garden, working it underneath and between the stones to set them firmly in place.
Bury the stones up to a third of their depth, firming them in place.
Leave the areas between the stones unfirmed and add the following mix over the area to create planting pockets.
One part loam (ideally sterilised loam, but in a pinch garden soil can be used)
One part horticultural grit
One part leafmould or coir

Question 7

Creating an alpine trough

Answer 7

Made from stone/ reconstituted stone/ cement / hypertufa
50%compost 50%grit
Layer of grit in the bottom then compost then plant then mulch with layer of grit or gravel

Question 8

What is hypertufa

Answer 8

Mixture of sand/cement/peat

Question 9

Maintenance of rock garden

Answer 9

Watering not really necessary except in long periods without rain
Trim in autumn to keep compact
Keep weeds down
Look out for pests such as slugs and snails
Diseases such as grey mould