Georgia Gardener Newsletter Design Tip: August 6, 2009

The Color Purple

Purple Coleus Blackie Sweet Potato Vine

I've always had a saying when it comes to showy plants in the garden: "Flowers are fleeting but foliage is forever." Well, technically some foliage isn't forever but it certainly lasts a lot longer than the flowers of most plants. For that reason I've always been attracted to plants with variegated or colored foliage (other than green). I think the design possibilities for these plants are much broader than standard green plants, not that I have anything against them either.

Plants with purple foliage are quite numerous and cover the entire range of plant types from trees to annuals. While most plants don't have leaves that are true purple, they can range from reddish/purple to almost black. Plants with this color of foliage will blend nicely with plants that have leaves and flowers that are slightly different or hue or are complementary which will be in the yellow to green spectrum. With each category below I will list some good companion plants.

The plants that I discuss below are by no means the only ones available and there have been entire books dedicated to the subject.

Trees with Purple Foliage

There are several trees that have purple-ish foliage. I have found that with some of these (*) the foliage emerges purple but tends to fade to green as the season progresses. Except where noted, you will find that the trees listed below often have better foliage color when planted in full sun. These include:

Purple Leaf Plum (Prunus Cerasifera)
Forest Pansy Redbud* (Cercis canadensis 'Forest Pansy')
Canada Red Chokecherry** (Prunus virginiana 'Canada Red' or 'Schubert')
Royal Purple Smoke Tree (Cotinus coggygria 'Royal Purple')
Japanese Maple (Acer palmatum) - some varieties - partial shade
Flowering Crabapples (Malus spp.) - some varieties
Purple European Beech** (Fagus sylvatica 'Dawyck Purple' and 'Atropurpurea'

The trees marked by double asterisks (**) are worth trying and are not commonly seen growing in the south. Of note, the Canada Red Chokecherry has the reverse habit - it's new foliage emerges green and then changes to purple as the season progresses.

Good companion plants for these include underplantings of any variety of golden coral bells (Heuchera spp.), golden varieties of sedge (Carex spp.) and Creeping Jenny (Lysimachia nummularia ‘Aurea’) - kept in bounds.

Forest Pansy Redbud Canada Red Chokecherry

Shrubs with Purple Foliage

Shrubs with purple foliage are actually quite easy to find and becoming more abundant each year. Like the trees, most of these do better when planted in full sun. Loropetalums are probably the best known of the bunch. I have found a wide range of foliage color and durability between the various cultivars of loropetalums. Many start out in spring with vibrant purple foliage that fades to dull purple or green by the end of summer. The best way to counteract this is to buy varieties that hold their color (listed below) and keep them pruned to promote fresh purple leaves with nitrogen fertilizers.

Loropetalum (Loropetalum chinense Purple Diamond and Purple Pixie)
Ninebark** (Physocarpus opulifolius 'Seward', 'Monlo')
Elderberry** (Sambucus nigra Black Lacetm, 'Purpurea', 'Gerda')
Weigela (Weigela florida Midnight Winetm, Wine & Roses®)

Those with double asterisks (**) once again are not commonly seen in the south but are worth a try. One plant you won't see listed here is barberry (Berberis thunbergii). This thorny shrub is listed as invasive in the southeast.

Good companion plants include hybrid golden spireas (Spiraea x bumalda 'Limemound', 'Gold Flame', 'Golden Princess'), daylilies with pale lavender, pink or golden flowers, gold mop false cypress (Chamaecyparis pisifera 'Gold Mop' or 'Mops'), mother lode juniper ( Juniperus horizontalis 'Mother Lode'), Tiger Eye Sumac (Rhus typhina 'Bailtiger') yellow roses and yellow lantana.

Purple Diamond Loropetalum Unknown Espalier Loropetalum

Perennials with Purple Foliage

Every year it seems as though there are more to choose from. The same is true for the annuals. As it turns out, we have perennials with purple leaves that are suitable for sun or shade. Most of these plants tend to hold onto their foliage color without the problems often experienced by the trees and shrubs. Purple perennials for the sun include:

Chocolate Snakeroot (Eupatorium rugosum 'Chocolate')
Purple Heart (Setcreasea pallida 'Purple Heart')
Purple Knockout Lyre-leaf Sage (Salvia lyrata 'Purple Knockout') - shade also
Husker Red Penstemon (Penstemon digitalis 'Husker Red')
Black Elephant Ear (Colocasia esculenta 'Black Magic')
Sedum (Sedum spp.) - several varieties
Purple Spurge (Euphorbia dulcis 'Chameleon')

Purple perennials for shade include:

Coral Bells (Heuchera spp.) - many varieties
Purple Shamrock (Oxalis regnellii 'Atropurpurea')
Purple Bugbane (Cimicifuga spp. 'Brunette', 'Hillside Black Beauty')
Black Mondo Grass (Ophiopogon planiscapus 'Nigrescens')

One plant you won't see listed here is ajuga. It's a thug. I always recommend using the Purple Knockout sage listed above. It also spreads but it is a native plant.

For sun, good companion plants include those listed above with the shrubs as well as purple iceplant (Delosperma cooperi), Sweet Kate spiderwort (Tradescantia x 'Sweet Kate'), mums and asters with appropriately matched flowers, perennials with white flowers, perennials with silver foliage such as lamb's ears (Stachys byzantina) and wormwood (Artemisia spp.).

For shade, good companion plants include those listed above with the trees, golden varieties of hosta, golden varieties of coral bells (Heuchera spp.) and Japanese forest grass (Hakonechloa macra ‘Aureola’).

Black Elephant Ears Purple Knockout Lyre-leaf Sage

Annuals with Purple Foliage

If you are leary about introducing plants with purple foliage to your landscape, you could always start out slowly by planting annuals instead. If you don't like the look of purple foliage - up they come at the end of the season or sooner. As it turns out, we have quite a few summer annuals and one or two winter ones and at least one for shade. These include:

Purple Basil (Ocimum basilicum 'Purple Delight') - can be aggressive
Cordyline (Cordyline australis) - several varieties
Purple Fountain Grass (Pennisetum rubrum)
Millet (Pennisetum glaucum 'Purple Majesty')
Persian Shield (Strobilanthes dyerianus)
Blackie Sweet Potato Vine ((Ipomoea batatas 'Blackie')
Ornamental Cabbage and Kale (Brassica oleracea) - a cool season annual
Purple Caladium (Caladium bicolor) - many varieties for shade to part sun

To maintain the vigor of these annuals make sure they are planted in well-amended soil and fertilized regularly. Poor nutrition and bad soil could cause these plants to have muted foliage color.

Good companion plants include any of those listed above as well as Marguerite sweet potato vine, golden varieties of coleus, caladium and other such annuals. For the ornamental cabbages and kales, try mixing them with yellow pansies, early blooming daffodils and other early bulbs.

Purple Fountain Grass Ornamental Kale

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