This perennial is neat compact mass, 4 to 8 inches tall, which spreads by surface rhizomes, has 3 to 4 inch long grey-green leaves with linear-shaped, toothed margins. Long stalks bear solitary flowerheads 2 inches across with dark purple ray florets and central discs that age to gold. This sun-loving perennial withstands adverse conditions, but grows best in well-drained soil with adequate moisture. Can be grown from seed. Pinch tips of plants to encourage a bushier, sturdier plant.Important Info : Sometimes referred to as Osteospermum var. compactum 'Blackthorn Seedling'.
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CharacteristicsCultivar: var. compactum 'Blackthorn'
Size: Height: 0.33 ft. to 0.67 ft.
Width: 0 ft. to 0 ft.
Plant Category: annuals and biennials, perennials,
Plant Characteristics: low maintenance, seed start,
Foliage Characteristics: medium leaves,
Flower Characteristics: long lasting, single,
Flower Color: purples,
Tolerances: drought, heat & humidity, slope,
Bloomtime Range: Late Spring to Early Fall
USDA Hardiness Zone: 9 to 10
AHS Heat Zone: Not defined for this plant
Light Range: Sun to Full Sun
pH Range: 5.5 to 8
Soil Range: Some Sand to Clay Loam
Water Range: Dry to Normal
FertilizingHow-to : Fertilization for Annuals and Perennials
Annuals and perennials may be fertilized using: 1.water-soluble, quick release fertilizers; 2. temperature controlled slow-release fertilizers; or 3. organic fertilizers such as fish emulsion. Water soluble fertilizers are generally used every two weeks during the growing season or per label instructions. Controlled, slow-release fertilizers are worked into the soil ususally only once during the growing season or per label directions. For organic fertilizers such as fish emulsion, follow label directions as they may vary per product.
LightConditions : Full Sun
Full Sun is defined as exposure to more than 6 hours of continuous, direct sun per day.
WateringConditions : Normal Watering for Outdoor Plants
Normal watering means that soil should be kept evenly moist and watered regularly, as conditions require. Most plants like 1 inch of water a week during the growing season, but take care not to over water. The first two years after a plant is installed, regular watering is important for establishment. The first year is critical. It is better to water once a week and water deeply, than to water frequently for a few minutes.
PlantingHow-to : Preparing Garden Beds
Use a soil testing kit to determine the acidity or alkalinity of the soil before beginning any garden bed preparation. This will help you determine which plants are best suited for your site. Check soil drainage and correct drainage where standing water remains. Clear weeds and debris from planting areas and continue to remove weeds as soon as they come up.
A week to 10 days before planting, add 2 to 4 inches of aged manure or compost and work into the planting site to improve fertility and increase water retention and drainage. If soil composition is weak, a layer of topsoil should be considered as well. No matter if your soil is sand or clay, it can be improved by adding the same thing: organic matter. The more, the better; work deep into the soil. Prepare beds to an 18 inch deep for perennials. This will seem like a tremendous amount of work now, but will greatly pay off later. Besides, this is not something that is easily done later, once plants have been established.
How-to : Pinching and Thinning Perennials
Once you plant a perennial, it does not mean that you will enjoy years of maintenance-free gardening. Perennials need to be cared for just like any other plant. One thing that distinguishes perennials is that they tend to be active growers that have to be thinned out occasionally or they will loose vigor.
As perennials establish, it is important to prune them back and thin them out occasionally. This will prevent them from completely taking over an area to the exclusion of other plants, and also will increase air circulation thereby reducing the incidence of diseases like botrytis and powdery mildew.
Many species also flower abundantly and produce ample seed. As blooms fade it is advisable to deadhead your plant; that is, to remove spent flowers before they form seed. This will prevent your plants from seeding all over the garden and will conserve the considerable energy it takes the plant to produce seed.
As perennials mature, they may form a dense root mass that eventually leads to a less vigorous plant. It is advisable to occasionally thin out a stand of such perennials. By dividing the root system, you can make new plants to plant in another area of the garden or give away. Also root pruning will stimulate new growth and rejuvenate the plant. Most perennials may be successfully divided in either spring or fall. Do a little homework; some perennials do have a preference.
How-to : Planting Perennials
Determine appropriate perennials for your garden by considering sun and shade through the day, exposure, water requirements, climate, soil makeup, seasonal color desired, and position of other garden plants and trees.
The best times to plant are spring and fall, when soil is workable and out of danger of frost. Fall plantings have the advantage that roots can develop and not have to compete with developing top growth as in the spring. Spring is more desirable for perennials that dislike wet conditions or for colder areas, allowing full establishment before first winter. Planting in summer or winter is not advisable for most plants, unless planting a more established sized plant.
To plant container-grown plants: Prepare planting holes with appropriate depth and space between. Water the plant thoroughly and let the excess water drain before carefully removing from the container. Carefully loosen the root ball and place the plant in the hole, working soil around the roots as you fill. If the plant is extremely root bound, separate roots with fingers. A few slits made with a pocket knife are okay, but should be kept to a minimum. Continue filling in soil and water thoroughly, protecting from direct sun until stable.
To plant bare-root plants: Plant as soon as possible after purchase. Prepare suitable planting holes, spread roots and work soil among roots as you fill in. Water well and protect from direct sun until stable.
To plant seedlings: A number of perennials produce self-sown seedlings that can be transplanted. You may also start your own seedling bed for transplanting. Prepare suitable planting holes, spacing appropriately for plant development. Gently lift the seedling and as much surrounding soil as possible with your garden trowel, and replant it immediately, firming soil with fingertips and water well. Shade from direct sun and water regularly until stable.
ProblemsDiseases : Verticillium or Fusarium Wilt
Wilts may be contracted through infected seed, plant debris, or soil. This fungus begins and multiplies during the cool, moist season, becoming obvious when weather turns warm and dry. Plants wilt because the fungus damages their water conducting mechanisms. Overfertilization can worsen this problem. Able to overwinter in soil for many years, it is also carried and harbored in common weeds.
Prevention and Control: If possible, select resistant varieties. Keep nitrogen-heavy fertilizers to a minimum as well as over-irrigating as they encourage lush growth. Practice crop rotation and prune out or better yet remove infected plants.
Pest : Aphids
Aphids are small, soft-bodied, slow-moving insects that suck fluids from plants. Aphids come in many colors, ranging from green to brown to black, and they may have wings. They attack a wide range of plant species causing stunting, deformed leaves and buds. They can transmit harmful plant viruses with their piercing/sucking mouthparts. Aphids, generally, are merely a nuisance, since it takes many of them to cause serious plant damage. However aphids do produce a sweet substance called honeydew (coveted by ants) which can lead to an unattractive black surface growth called sooty mold.
Aphids can increase quickly in numbers and each female can produce up to 250 live nymphs in the course of a month without mating. Aphids often appear when the environment changes - spring & fall. They're often massed at the tips of branches feeding on succulent tissue. Aphids are attracted to the color yellow and will often hitchhike on yellow clothing.
Prevention and Control: Keep weeds to an absolute minimum, especially around desirable plants. On edibles, wash off infected area of plant. Lady bugs and lacewings will feed on aphids in the garden. There are various products - organic and inorganic - that can be used to control aphids. Seek the recommendation of a professional and follow all label procedures to a tee.
Fungi : Downy Mildew
Downy Mildew, a fluffy white fungal growth that develops on the underside of leaves, is most common during cool, humid conditions. Foliage often discolors and is stunted.
Prevention and Control: Use disease free plants and space far enough apart so that air circulation is good. Remove and discard infected leaves or even entire plants. Use a recommended fungicide and always follow the directions on the label.
MiscellaneousConditions : Rabbit Tolerant
As cute as they are, rabbits can really damage a vegetable garden. Young, tender lettuce plants seem to be their favorite. If a free-roaming dog is not a possibility for you, consider installing raised vegetable beds and covering tender shoots with netting. If you have ample room, you can opt to plant enough for you and the bunnies. Scents don't always repel animals, as they get used to them and are often washed off in the rain.
Conditions : Slope Tolerant
Slope tolerant plants are those that have a fibrous root system and are often plants that prefer good soil drainage. These plants assist in erosion control by stabilizing/holding the soil on slopes intact.
Glossary : Biennial
Biennial is a plant that takes two growing seasons to produce flowers and fruit. The first growing season, the plant stays in a rosette form, producing mainly foliage and roots. The second growing season the plant bolts, producing flowers and fruits or seeds.
Glossary : Herbaceous
Herbaceous refers to a non-woody plant that dies back at the end of its growing season, generally after frost or during the fall of the year. The rootstock of perennials will overwinter, providing the plant is hardy in that area, and resume growth in the spring.
Glossary : Perennial
Perennial: traditionally a non-woody plant that lives for two or more growing seasons.
Glossary : Seed Start
Seed Start: easily propagated from seed.
Glossary : pH
pH, means the potential of Hydrogen, is the measure of alkalinity or acidity. In horticulture, pH refers to the pH of soil. The scale measures from 0, most acid, to 14, most alkaline. Seven is neutral. Most plants prefer a range between 5.5 and about 6.7, an acid range, but there are plenty of other plants that like soil more alkaline, or above 7. A pH of 7 is where the plant can most easily absorb the most nutrients in the soil. Some plants prefer more or less of certain nutrients, and therefore do better at a certain pH.