It has come out of nowhere into a rising arc of popularity – and why not? This flowering plant not only brings riotous good cheer, it is easy to grow and equally easy to maintain.
Hard to Pin Down
Is it a subshrub or a shrub? A perennial or an annual? Single or clustered? Hard to pin down, the African Daisy is all of those!
Osteospermum species are perennials but the plant has been hybridised and cultivated for ornamental uses and most cultivars are annuals. To add to the confusion, sometimes the perennials are grown as annuals while the annuals, depending on their hardiness or the climate, such as U.S.D.A. zones 10 and 11, become perennials. In the United Kingdom whether one or another Osteospermum is a ‘perennial’ or an ‘annual’ simply depends on whether or not it can survive a British winter and/or is allowed to do so. Osteospermum ecklonis and Osteospermum jucundum are two species which can, and, therefore, can be and often are ‘perennials’ in the U.K.
Though Osteospermum as an annual is a subshrub, when it is a perennial it grows to be a shrub. Usually one stalk bears a single flower but some cultivars produce lush corymbs. The flowers comprise of a prominent central disk – the disk floret – and the petals – the ray floret. Most varieties’ petals are typically flat and narrow but some have curled, spoon-shaped petals.
Osteospermum should not be confused with the related plant Dimorphoteca but it often is.
Some shrub species such as Osteospermum ecklonis reach a height of one metre but in contrast, the subshrub Osteospermum ‘Cannington Roy’, like Osteospermum ‘Snow Pixie’, grows to only 15 centimetres – merely 5 centimetres more than the length of O. ecklonis’s leaves!
Talking of leaves, the diversity within Osteospermum extends even to that part of the plant. The leaves are lanceolate or ovate, with toothed or entire margins, depending on the species or cultivar. Furthermore, one and the same species, for example Osteospermum ecklonis, can put out leaves of different morphologies! As a general rule, toothed leaves indicate a hardy variety. Such varieties, rather than growing upright, usually spread along the ground forming clumps.
The African Daisy has about 70 species and an increasing number of cultivars; indeed, the Royal Horticultural Society lists over 900 varieties. Many of these varieties are notable not only for the ray florets but even for the central disks which sometimes provide a fine contrast to the rays setting them off or sometimes are of deep or metallic colours that are attractive in their own right. Some varieties have bicoloured disks; others have rays in gradated shades.
This humble daisy spoils both gardeners and florists for choice as it can light up a flower bed just as well as a floral arrangement.
Background & Origins
Osteospermum is surely one of the few plants not named after (some part of) the plant itself – it is named after its seeds! Osteon is Greek for bone and spermum is Latin for seeds; thus, the composite name describes the ‘bone-hard’ quality of the seeds. Probably African Daisy is a more apt name for . . . an African Daisy! It is also called Cape Daisy, Cape Marigold, and Star of the Veldt. South African species are also called Arctotis. This plant of many names is also one of many colours – besides white and cream, the ray florets come in yellows, pinks, and purples, over and above which some cultivars produce orange and even reddish blooms. Then there are the disk florets…
The plant is native to most of the African continent, where it is found in veldts and grasslands, and to much of the Arabian Peninsula. Plants were brought to Europe in the 19th Century where they have been crossed and cultivated, especially during the past few decades. In nature, African Daisy is phototropic – the flowers face the sun. Moreover, under cloud cover and at night the flowers close. Over the years cultivars were bred for, among other things, the flowers to remain open under cloud and through dark but a few cultivars retain the charming habit of curling in for the night.
Regardless of whether the flowers remain open or shut up shop at night, our personal top ten choices for the most attractive, prettiest cultivars follow in no particular order.
- O. ‘James Elliman’: Bearing flowers on upright stalks, the petals are somewhat splayed and separated; as for its deep and hard but pastel pink hues, they are unmatched.
- O. ‘Lady Leitrim’: The yellow-and-black bi-coloured disk floret is at least matched by the ray floret which, upon blooming, is white at the base gradating to a pale purple.
- O. ‘Buttermilk’: Aptly-named, the petals are indeed ‘buttermilky,’ being white at the base and becoming a creamy yellow nearer the tips, contrasted by a midnight blue disk.
- O. ‘This is Voltage!’: A deep golden-yellow disk and overlapping petals of an intense electric yellow hue, this is another aptly-named and eye-catching cultivar.
- O. ‘Astra Orange Sunrise’: The brown disk is nothing to shout about but the chunky flower has broadish rays of a warm and mellow orange hue that is as unusual as it is lovely.
- O. jucundum ‘Langtrees’: The largeish flower’s rays are narrow and close-set, and their gentle, soothing purple-pink hue is equally gently contrasted by the yellow disk.
- O. ‘Killerton Pink’: Even its bi-coloured disk floret of deep blue and yellow is put in the shade by the petals which have a pale pink tint with a distinct hint of bluish-purple.
- O. ‘Sunny Mary’: The broad and flat flowers have ray florets that can be of an intense chemical magenta centred by a metallic black disk to make for an arresting and vivid bloom.
- O. ‘Sunadora Marbella’: A lush flower with overlapping petals, the brown disk is wonderfully complemented by rays that are light yellow at the base turning into a golden amber.
- O. ‘Weetwood’: The classic daisy look: with a yellow disk and perfectly-shaped and -proportioned petals that are a solid, pure white, this cultivar is a standard-bearer of sorts.
Feeding, Care & Growing Tips
As a native of Africa, African Daisies grow well enough in sandy, chalky, and even stony soils, which is not to say that they should be grown in such soils. They need loose, light soils without much in the way of clay or manure. They prefer acidic soils, ideally in the region of pH 5.0 to 6.0, but pH up to 7.0 is perfectly fine too.
Mature specimens can tolerate a dry spell for a while but not waterlogged ground so make certain that your soil is well-drained. Moist soil, however, works well for the plant.
Water a transplanted plant every two or three days for the first fortnight, then twice a week for the next fortnight, and then once a week.
Though it may seem counter-intuitive for a genus of African origin, the plants do not do well in high heat, and cultivars in particular are averse to high humidity. In fact, most Osteospermums like coolish summers which lead to profuse blooming. However, these plants prefer full sun.
You can increase the likelihood of plentiful and robust blooms by feeding African Daisies a sprinkling of 5-5-5 fertilizer every three weeks just before and during flowering season.
Although Osteospermum does not need pruning as such, it always helps. What it does need is deadheading. As soon as flowers wilt, cut them to the level of the set of leaves just below. Thus, flowers will not go to seed and, therefore, blooming will be prolonged.
If a plant looks overgrown or straggly by mid-July, give it a trim. Using secateurs, prune the plant by cutting off one-third to one-half of the longer stems, focussing on the older ones. This type of summer haircut will kick off a spurt of new foliage and also encourage further blooming.
You can forestall straggly plants from the very outset. Pinch off the growing tips of the young plants twice in the early summer before any buds appear. This will result in a more compact and bushy plant.
Finally, in the warmer climes of USDA zones 9 and higher, African Daisy can be pruned annually. You can cut it back to the ground in early spring.
When To Plant Osteospermum
Plant seeds indoors in containers 6 to 8 weeks before the last frost. Cover seeds with only the barest sprinkling of soil as they need light to germinate. Otherwise, simply press seeds partway into the soil. Water them twice a week initially and then as described in section Feeding, Care & Growing Tips. Seedlings will sprout in about 2 weeks. Water at the ground level and not on the leaves to prevent fungal diseases.
Seedlings can be transplanted into beds after the last frost. Transplant seedlings about 25 centimetres apart. It may be late summer before seed-grown plants produce flowers. Established plants or store-bought plants will bloom earlier, from early summer or, depending on the variety, late spring.
Most varieties will bloom in all their glory from May to early July but after that, as summer sizzles the daisies dwindle.
How To Best Use Osteospermum
The African Daisy is best shown off in sheets and swaths of flowering plants, mimicking how it occurs in nature, instead of in ones or twos.
On patios and decks, a line of containers of bright-coloured varietals set along the edge or on the parapet will bring low-key ornamental value to your enclosure.
African Daisy can be used to line or edge walkways and pathways. Try alternating patches with varieties in soft or pastel shades, say whites and pinks or yellows and purples.
You can also use these plants to border beds whose centrepieces are showier or rarer flowers; to do so, use varieties of shorter height and complimentary, gentle colours.
Finally, you can set loose an assortment of varieties and a gamut of colours in a good-sized vacant patch of your yard, being sure that no matter which ones you plant the results will bring merriment and good cheer.
The open, uncomplicated structure of the flower combined with the colours that range from soothing, pastel shades to bold, vibrant hues make Osteospermum a top choice for floral arrangements, specifically mass arrangements, and also for larger bouquets. It is not recommended for emphasis or balance but is an excellent pick to achieve proportion, harmony, or rhythm.
Habitat & Growing Conditions
The African Daisy’s natural habitat are the veldts, savannahs, and grasslands of Africa and Arabia where they grow in relatively light soil and even poor soil. They are also found in and near dry forests. Their species – as opposed to most cultivars – thrive in sub-tropical regions with high humidity and also in humid warm-temperate regions.
While African Daisies appreciate good soil, they grow happily enough in most any old soil. Most varieties are unfussy, low-maintenance plants. All they need is regular watering but mature plants can make do even without water as they simply go dormant, springing back to life when they get water.
Depending on the variety, the plant is hardy to USDA zones 9 and 10 or 10 and 11. Osteospermum species and many cultivars are frost-tender or, at best, frost half-hardy.
Where To Buy Osteospermum
Osteospermum’s continuing rise in popularity is matched by a corresponding increase in its availability. Most nurseries and garden centres have ready stocks in an array of varieties. Potted plants, as well as seeds, are available online. Horticultural specialists sell established Osteospermum varieties as well as their own brand-new cultivars through their own websites.
Instead of buying, you can ‘make’ new African Daisy plants yourself by propagating them through cuttings from late spring to late summer.
Common Diseases & Problems
This tough ‘bone-hard’ plant is relatively free of diseases and is pest-resistant, and more so when it is in good health and not under stress.
In high humidity, Osteospermum can contract two fungal diseases, downy mildew and grey mould. In either case, promptly cut off the affected areas of the plant. If the plant is indoors, reduce humidity and increase air circulation. If it is outdoors, see that it is not covered or closed-in by other foliage.
While downy mildew cannot be controlled with consumer-class fungicides, to combat grey mould, after cutting off the diseased parts, you could swab and rub adjacent areas with a very diluted solution of thiophanate methyl.
The other problem that may affect this plant is aphids. They are one of the most destructive of pests because of how rapidly they multiply and the amount of damage they cause. Spray or rub a one percent solution of Orthene on the infestation and on the surrounding parts and foliage.
Frequently Asked Questions
Are osteospermum hardy plants?
In general, Osteospermum plants are half-hardy, that is they can survive one or two touches of frost but not repeated frosts. More specifically, hardiness depends on the particular species or cultivar. For example, Osteospermum ‘Silver Sparkler’ is not even half-hardy whereas Osteopermum jucundum is actually hardy. Varieties with spoon-shaped petals or smooth- or entire-margined leaves indicate a tender or, at best, a half-hardy variety.
Is osteospermum perennial or annual?
Either and both – it depends on the particular Osteospermum and the climate. The species grow in their natural habitats as perennials while the cultivars are grown as annuals. However, in warm climates that do not undergo a frost, cultivars can continue as perennials while in cold climates species are grown as annuals. Also see section Hard to Pin Down.
How big do osteospermum get?
The most common height for Osteospermum varieties is between 30 and 40 centimetres with an average of about 36 centimetres. A few species such as Osteospermum ecklonis can hit a height of one metre.
How can I overwinter osteospermum?
Overwintering Osteospermum plants outdoors is difficult in heavy soils or frost-prone areas. Indeed, the best and most reliable way to overwinter this plant in the United Kingdom is by taking cuttings, preferably softwood cuttings in the summer. Plant the cuttings in pots and keep them indoors, optionally under glass.
Do deer eat osteospermum?
They do if they must but not if they can help it. Deer avoid this plant as do rabbits.
Is osteospermum poisonous to cats or dogs?
They are not poisonous to cats or dogs, though they can cause gastrointestinal tract irritation or diarrhoea if ingested in large quantities.