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Coleus for the sun

Coleus have long been an important component of shade plantings; whether planted in the ground or grown in containers, they have traditionally been popular plants for those spots in the garden that receive little direct sun. The older varieties, such as the “Rainbow” series, are all suitable for use in the shade and in fact, will not perform well in sun. The leaves will burn and turn brown around the edges and if the plants are exposed to too much sun, the plants will simply die.

Plant breeders, during the last decade or so, have been at work developing coleus that will grow — and flourish — in full sun. The foliage is often brightly coloured and direct sun is required to bring out the vibrant hues; grow them in the shade and the plants are not nearly as colourful and may revert to being almost plain green. Sun coleus are strong, sturdy plants and not nearly as “soft” in structure as are the older shade coleus varieties.

The development of these sun coleus has greatly increased the ways that we can use them in the landscape — as colourful hedges, included in mixed containers, as specimens, and generally, in all the ways that we use other colourful annuals grown in the sun.

Although sun coleus are advertised as being suited to full sun, I find that many of them perform best in a location which has some protection from harsh midday sun. The colouration will vary greatly depending on the amount of sun the plant receives — one grown in almost full shade will have completely different colouration from one grown in almost full sun. As a plant receives more sun, it produces more chlorophyll to protect its leaves and this affects the colour of the leaves. In full sun they may darken more than you want, while in full shade they may be paler than you prefer.

I find that I have to experiment with sun coleus and find out which level of sun exposure produces the best results with each variety. For this reason I usually grow my coleus in containers so that I can move them around the garden if the need arises. For example, I have found that “Kingswood Torch,” a brilliant-dark-red variety, is absolutely stunning if exposed to full sun. “Aurora,” on the other hand, gets too dark and I think the colour gets “muddy” in full sun so I plant it where it gets morning and early-afternoon sun but shade in the hot afternoon.

Sun coleus can be combined in containers with geraniums, salvia, calibrachoa, marigolds and many other plants to create a colourful composition. Most get quite large; by the end of the summer the plants can be 50 cm tall. This makes them great to use at the back of a container to provide a “backdrop” for the flowering plants in the foreground of the arrangement. Their upright growth habit and sturdy stems ensure that they remain self-supporting and retain their attractive shape.

Names like “Fishnet Stockings,” “Rustic Orange,” “Burgundy Sun,” and “Electric Lime” reflect the wide range of colours and leaf patterns available. Sun coleus will provide unique, vibrant colour to the summer garden.

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