Building A Rock Garden On Flat Ground.(2) Proportions

(A) Dimensions
Naturally, the length and width of your rock garden depends on how much space you have to spare. The height is a matter of personal taste, but aim to keep a small rock garden fairly low.
(b) High Points.
An undulating surface looks wonderful. The high point of the rock garden can be in the centre or towards either end of the bed.
If your Rock garden is to be long and narrow, two more high points can be added. Both are progressively shorter than the main high point.

One high point in a small rockery is normally enough. Place it off centre, for the most pleasing effect.

Add Some Height.

Many types of dwarf shrubs are still too tall or rampant growing to be suitable for rock gardens.
Check out my rock garden shrub tips for those types that will add the desired maturity and height variance, without outgrowing their welcome.

Sorbus reducta.

A tiny rowan, growing to no more than 1 ft tall. Fully hardy. Forms a thicket of greyish-green divided foliage.
Flat heads of white flowers in early summer are followed by reddish-pink berries in early fall.
Any good garden soil in full sun.

Andromeda.

Andromedas are related to heathers and require the same conditions: Full sun and acid soil.
They are fully hardy, have evergreen foliage and delicate bell-shaped blooms on the stem tips from late spring to early summer.
The most commonly available sorts are:
Andromeda polifolia: Pink blooms. 1.5 ft tall
Andromeda polifolia "Alba.": White, 1.5 ft tall.
Andromeda polifolia "Compacta": Pink, 1 ft tall.

Siting.

The siting of your new rock garden is very important. An open, sunny aspect is best.
Choose an area of the garden away from trees and high walls.
Alpine plants will not grow well in shade and may be killed by the drips from trees.

Betula nana.

Rock Garden Shrubs : Betula nana.
Betula nana is an unbelievably small form of the familiar Birch tree. Very hardy, it is known as the Arctic Birch. Growth is twiggy and reaches no more than 1 ft. tall.
A curiosity, but worth growing also for the butter yellow fall foliage and the tiny yellow birch catkins in spring.

Building the Rock Garden On A Slope.

Strip the slope af vegetation, ensiring that all perennial weed roots are completely removed.
Start from the base. Set the stones with half to two thirds of their depth buried.
It should look like a natural outcrop so following the natural contours and for best results, space the stones irregularly.
Use the largest stones at the base of the slope and the smaller stones towards the top.

Helianthemum.

The Rock Roses are evergreen, spreading, with a long flowering period. May-August.
Must have full sun and poor, free-draining soil. Hardy, but can be damaged in severe winters.
Good varieties are:
Helianthemum "Ben Hope": Red 9"Tall.
Helianthemum "Ben Affleck": Orangy-Pink 12"tall.(named after the Scottish Mountain, not the actor!).
Helianthemum "Ben Nevis": Orange. 9"Tall
Helianthemum "Ben More": Coppery orange. 12 tall.
Helianthemum " The Bride": White. 12" tall.
Helianthemum "Raspberry Ripple": White and red blooms. 8"tall.
Helianthemum "Wisley Primrose" Soft yellow 9"tall.

Building A Rock Garden On Flat Ground.(1) The Outline.

An island rock garden should have an irregular, flowing outline. Avoid geometric shapes and straight lines.
A flowing, curved outline looks natural and is easy to navigate a mower around.
Lay a hose pipe on the lawn to form the proposed outline. Stand back and view from different aspects. Adjust the outline if necessary and when you are completely happy, trickle some sand around the outside of the hose to mark the bed shape on the grass.
Remove the turf and dig the bed over to a depth of 12". Remove all perennial weed roots

Soil Type.

The main requirements for most Alpine plants is that the soil should be free draining, especially so in winter.
If your soil is on the heavy side it can easily be made suitable by digging in horticultural grit.
Most Alpine plants will do well in ordinary garden soil

Daphne.

Choice early blooming fragrant slow growing shrubs. All do best in peaty soil in full sun or semi-shade. Fully hardy.
Daphne mezureum: Deciduous. Purple blooms followed by red berries. 1.5 ft.
Daphne mezureum "Alba" As above , but with white flowers.
Daphne cneorum : Evergreen. Pink blooms in late spring. 9" tall

Cytisus.

The shorter Brooms provide an excellent splash of colour during early summer. The branches are bright green, giving year round interest. All are fully hardy and do well in ordinary garden soil in a sunny aspect.
Good types are:
Cytisus x kewensis: Arching branches. Cream flowers. 18" tall.
Cytisus purpureus: Arching branches. Purple blooms. 18"tall.
Cytisus x beanii: Arching branches. Bright yellow flowers. 1 ft tall.

Genista

Good, reliable yellow blooming small shrubs. All prefer a sunny aspect and ordinary garden soil .Fully hardy.
Some excellent types are:
Genista tinctoria : 1 ft. tall blooms early summer.
Genista lydia: 2 ft tall. Mid summer.

The Stone.

Sandstone or limestone are best. Concrete made to look like stone invariably doesn´t.
Stones used should be in a variety of sizes, avoid the bitty effect of using stones the same size. Stone has a grain like wood, always make sure the grain runs in the same direction horizontally.
A good tip is that less is more: It is better to use a few large rocks, than masses of small ones.

Gaultheria shallon.

An evergreen shrub with pink lily of the valley type blooms in early summer and wine red berries in fall. Must have damp peaty soil and some shade. 2 ft tall. Fully hardy.

Bulbs For Rock Gardens.

Get the proportions right and bulbs look fantastic in the rock garden. Many flower early, pushing their way through the mats of alpine plants , (which often disguise the dying foliage).
Grown in this way, dwarf bulbs never looked more at home.
Check out the following lists of bulbs for planting in the rock garden.
Late Winter Flowering:
Anenome blanda. Crocus tomasinianus, Crocus chrysanthus, Cyclamen coum, Eranthus hyemalis, Galanthus novalis, Hepatica nobilis, Iris reticulata, Iris danfordiae, Muscari
armeniacum,

Mid to late spring flowering:
Chionodoxia , Allium moly. Allium ostrowskianum, Erythronium, Bulbicodum vernum, Scilla
sibirica, Puschkinia libanotica,Tulipa tarda, Tulipa clusiana,Tulipa batalinii,Tulipa bakeri Narcissus bulbicodum, Narcissus caniculatus, Narcissus nanus, Narcissus pumilus, Narcissus campernelli.

Fall Flowering:
Cyclamen neopolitanum, Sternbergia lutea, Crocus longiflorus, Crocus iridifolius, Crocus sativus, Colchicum autumnale.

Bulbs For Rock Gardens.

Get the proportions right and bulbs look fantastic in the rock garden. Many flower early, pushing their way through the mats of alpine plants , (which often disguise the dying foliage),
Grown in this way, dwarf bulbs never looked more at home.
Check out the following lists of bulbs for planting in the rock garden.
Late Winter Flowering:
Anenome blanda. Crocus tomasinianus, Crocus chrysanthus, Cyclamen coum, Eranthus hyemalis, Galanthus novalis, Hepatica nobilis, Iris reticulata, Iris danfordiae, Muscari
armeniacum,

Mid to late spring flowering:
Chionodoxia , Allium moly. Allium ostrowskianum, Erythronium, Bulbicodum vernum, Scilla
sibirica, Puschkinia libanotica,Tulipa tarda, Tulipa clusiana,Tulipa batalinii,Tulipa bakeri Narcissus bulbicodum, Narcissus caniculatus, Narcissus nanus, Narcissus pumilus, Narcissus campernelli.

Fall Flowering:
Cyclamen neopolitanum, Sternbergia lutea, Crocus longiflorus, Crocus iridifolius, Crocus sativus, Colchicum autumnale.

Cassiope.

Cassiope are small shrubs related to heathers, so require acid peaty soil. They vary from heathers in that they need a sheltered , shaded site to do well. Fully hardy.
All have curious, scale-like evergreen foliage and bell-shaped flowers in spring.
Some good forms are:
Cassiope "Edinburgh": Masses of white bells in spring. 8" tall.
Cassiope lycopodiodes: Prostrate type, white blooms. 3" tall.
Cassiope fastigiata: Creamy/ white blooms. 1 ft tall.

Salix helvatica.

A very dwarf and compact willow for the rock garden. Needs damp soil and an open, sunny aspect.
The green foliage is grey underneath. The overall effect is a silver foliaged shrub, but with none of the hardiness problems.
The familiar, pussy willow-type silver then yellow catkins appear on the bare branches in late winter. 2 ft. tall. Fully hardy.