BLUE IS COOL
Blue is not a common colour in the garden. Sure we have all seen blue flowers, but when you stop and think about it, most flowers are shades of yellow, red, white or any colour other than blue, and often those flowers that are called blue are not really blue. For example, the Blue Moon Rose is lilac coloured, while the Rhododendron Blue Bell has a purple flower with a white and yellow throat.
It is even more difficult to find plant foliage that approaches blue in colour. Some hostas have a blueish foliage, the Blue Fescue has silvery blue leaves, there are also blue-toned conifers, but there aren't many other blue-foliaged plants.
USING BLUE IN THE GARDEN
Because it is so uncommon, blue can be used to create a different and unusual effect in your garden. If you choose to focus on and strive for a predominance of blue colours, you will create a garden that is truly unique. Blue colours are cool colours, and a garden that follows this type of colour scheme will be a wonderfully welcome place to relax during hot summer days.
The comparative scarcity of blue flowers means that you may have to compromise - perhaps using purple and mauve coloured flowers and grey foliage to complement the stronger blue shades. If you can't find enough plants with blueish foliage to suit your planting scheme (and there aren't many!), choose ones that have darker green or grey foliage in preference to the very light vibrant greens.
The choice of plant colours will also depend on your overall garden theme. For a romantic, cottage-style garden, you could try using the softer, silvery-blue or grey-blue shades; the more intense blues are suited to Mediterranean and Sante Fe style gardens.
As well as using plants with blue flowers and foliage, try to pick up the blue tones in statues, stones, paving, walls and fences. Furniture and garden accessories can also be painted various shades of blue to complement the garden. And if you're still looking for ways to feature blue colours, mosaics are an excellent way of bringing a whole range of blue shades into the garden.
To complement your blue theme, as well as giving the garden a really cool summery feel, you could make a feature of clear blue water. You don't need a swimming pool - a blue tiled pond or painted water bowl is sufficient.
Without making the garden too sunny and hot, try to bring at least some of the sky into view in the garden. On a bright summer day, the combination of blue sky, water, plants and garden accessories can be quite stunning.
- Agapanthus 'Baby Blue' - Dwarf form of Agapanthus with umbels of sky blue flowers in late spring-early summer.
- Brodiaea - Clusters of blue toned flowers held above strap leaves.
- Boophone - Warm climate bulb with purple-blue flowers.
- Hyacinthus - Scented blue flowers in spring (many coloured varieties available).
- Iris (Dutch Iris) - Bulbs with fine green leaves and blue iris flowers with a yellow centre in late winter-early spring. (White, mauve and yellow forms also available.)
- Muscari (Grape Hyacinth) - Small plants with blue tubular flowers.
- Scilla (Bluebell) - Variable blue flowering bulbs, best in cool climates.
- Ageratum houstonianum - Blue cultivars such as 'Blue Mink', 'Blue Blazer' and 'Blue Bouquet' are summer flowering annuals.
- Borago officinalis (Borage) - Sky-blue flowers borne on upright stalk with large green leaves.
- Centaurea cyanus (Cornflower) - Annual flower with vivid blue flowers in late spring-early summer. (Pink, mauve and white forms also available.)
- Delphinium - Highly attractive annuals/biennials that make stunning erect floral displays mostly in blue.
- Limononium sinuatum (Statice) - Annual with clusters of everlasting-type flowers in summer. Flower range includes blue, mauve, pink, white.
- Lobelia - Low-growing annual with dark blue or sky blue fan flowers in spring-early summer. (White, mauve and pink forms also available.)
- Myosotis sylvatica (Forget-me-not) - Annual with clusters of small blue flowers in late winter-early spring. Can become invasive in other parts of the garden.
- Nemophila (Baby Blue Eyes) - Small annual has blue flowers with a white centre. Flowers in spring-summer.
- Nigella (Love-in-a-mist) - Annual with feathery foliage and sky blue flowers in spring-summer. (White, pink and purple forms also available.)
- Viola (Pansies) - Small annuals with highly attractive blue flowers (many coloured forms available).
- Ajuga reptans (Blue Bugle Flower) - Groundcover with dark or bronzed green foliage and small blue spikes of flowers in spring.
- Campanula (Bellflower) - Herbaceous perennials, varying in size from small groundcovers to 1 m tall spires. Blue bell-shaped flowers in spring-early summer. (White and pink forms also available.)
- Delphinium - Herbaceous perennial to 1 m or more tall with spires of blue flowers in spring-summer. (Pink, lavender and white forms also available.)
- Dichorisandra thyrsiflora (Blue Ginger) - Tropical plant to 1 m, producing blue flowers in apical clusters.
- Gentiana - Several species of dwarf, perennial alpine plants well suited to rockeries and borders with masses of showy, bright blue flowers mainly in spring to summer.
- Meconopsis (Blue Poppy) - Herbaceous perennial with sky blue poppy flowers in late spring-early summer. Salvia uliginosa - Perennial with narrow spikes of blue flowers in summer-early autumn.
Blue Low-growing Plants
- Dampiera linearis - Groundcover with blue-purple flowers in spring-summer.
- Veronica prostrata - There are several blue flowering (in spring to summer) cultivars of this dwarf, mat forming plant suited to rockeries.
- Aristea - Small plant with star-like blue flowers.
- Allamanda violacea - Rambling shrub/trailer with violet flowers in warmer months.
- Clematis - Highly attractive climber for cool climates. Many colour forms available.
- Clitoria ternatea - Slender climber with attractive blue pea-shaped flowers.
- Solanum seaforthianum - Slender blue flowering climber with red berries.
- Sollya - Small climber with small blue flowers. It reguires good drainage and prefers mild climates.
- Thunbergia grandiflora - Hardy vigorous climber with sky-blue flowers up to 7.5 cm across.
- Wisteria - Deciduous vigorous climbers with hanging blue flowers (white and mauve forms available).
Blue Flowering Trees
- Azalea - Medium sized shrubs with blue/mauve/purple colour varieties.
- Browallia americana - Shrub to 1 m with mauve flowers and yellow centres.
- Brunfelsia pauciflora - Blue scented flowers that fade to white.
- Buddleia (Butterfly Bush) - Spreading arching medium shrub with blue flowers that attract butterflies.
- Ceanothus 'Pacific Blue' - Tall shrub with dense dark green leaves and profuse blue flowers in spring.
- Duranta 'Geisha Girl' - Stunning blue and white flowered shrub to 2 m, suitable for clipping.
- Echium (Pride of Madeira) - Hairy foliaged plant with erect spike of blue flowers.
- Eramthemum pulchellum (Blue Sage) - 1 m tall shrub with tight blue flowers above deep green leaves.
- Hydrangea macrophylla - Shrub with broad green leaves and large rounded flower heads in summer. Acid soils produce the darker blue flowers (ranging to pink in alkaline soils).
- Leschenaultia biloba - Small native shrub with deep blue flowers in spring. Short-lived in the garden.
- Otocanthus - Warm climate small to medium plant with blue and white flowers through most warm months of the year.
- Plumbago - Spreading shrub with mid-green leaves and clusters of blue flowers in summer.
- Rhododendron 'Blue Bell' - Blue toned flower on long-lived shrub.
- Syringa (Lilac) - Cool growing plants with vivid blues and lilacs.
Blue Coloured Foliage
- Bolusanthus (Blue Wisteria Tree) - 8 m deciduous tree with hanging blue clusters of flowers in spring.
- Jacaranda mimosifolia - Large deciduous tree with mauve-blue flowers in late spring.
- Tibouchina 'Alstonville' - 5 m tall small tree with purple-blue flowers in spring and autumn.
- Paulownia - Very fast growing deciduous tree to 8m with bluish flowers in spring.
- Acacia iteaphylla - Fast growing, dense shrub to 4-5 m tall, with bluish pendulous foliage. New growth may be initially pinkish-bronze in colour. Adaptable to a wide variety of conditions. Yellow flowers autumn to spring.
- Agave attenuata 'Nova' - Succulent plant with grey-blue hue foliage. Very popular with landscape designers.
- Aquilegia (Granny's Bonnets, Columbine) - Herbaceous perennial with lacy blue-green leaves. Blue and mauve flowered varieties are available (also pink, white, red, yellow flowers).
- Centranthus ruber - Small perennial to 60 cm tall, with blue-green foliage, and clusters of fragrant, white, pinkish to purple flowers in summer.
- Eryngium (Sea Holly) - Herbaceous perennial with stiff grey-blue leaves and thistle-like steel-blue flowers in summer.
- Hosta seiboldiana - Herbaceous perennial with large blue-green leaves. Grows best in shade.
- Linum perenne - Small perennial to 60 cm tall with blue-grey foliage, and blue flowers (in summer). It is suited to uses such as cottage gardens, perennial beds, as a border plant.
There are many conifers with bluish foliage. Some can grow very large, others are dwarf. There is a choice for just about any sized garden.
- Abies procera 'Glauca' - A pyramidal-shaped conifer to more than 5 m tall, with attractive pale-blue foliage. It prefers a fertile, moist, well-drained, acid soil.
- Cedrus atlantica 'Glauca' - Tall conifer to 35 m or more with pale-blue foliage. It is suited to large gardens and parks.
- Chamaecyparis lawsonia 'Allumni' - Very attractive, narrow pyramid-shaped conifer to 10 m or more, with pale blue foliage. It can be hedged.
- Chamaecyparis lawsonia 'Bleu Nantais' - Dwarf form of the Lawson Cypress to 1.5 m tall, with blue foliage.
- Chamaecyparis obtusa 'Sanderi' - Compact, dense-foliaged conifer to 2 m tall, with pale blue foliage. Outer foliage may turn purplish in very cold weather.
- Cupressus glabra - Quick growing, columnar or pyramid-shaped tree to 20 m tall. It has pale blue to bluish-green foliage. The cultivar 'Glauca' has even bluer foliage.
- Juniperus virginiana 'Sky Rocket' - Attractive, tall, narrow conifer to 5 m tall.
- Picea pungens 'Glauca' - Large tree eventually reaching 30 m or more (generally less in cultivation), with pale blue foliage. It is suited only to very large gardens or parks. The cultivar P. pungens 'Kosteri' has the outer parts of branches pendulous.
- Picea pungens 'Globosa' - Globe-shaped, dwarf cultivar of the Colorado spruce to 1 m tall.
- Picea pungens 'Montgomery' - Very attractive, cone-shaped shrub to 1.5 m tall with blue-silver foliage.