Diascia
( dye - ASS - ee - uh )
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At-A-Glance InformationDiascia, or Twinspur, is a genus of delicate perennial and annual flowering plants that need partial shade in the hottest climates and moderate to regular water to perform well. Native to South Africa, these popular beauties are related to Snapdragon. They carry blooms on spikes from spring through fall, and are great in rock gardens and in borders or containers (including hanging baskets) as well as mixed beds. Some species can also do very well as small-scale groundcovers. The bright colored blooms will attract pollinators like bees and butterflies to the garden.
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Diascia Species and Varietals
The genus Diascia is a member of the plant family Scrophulariaceae and includes around 70 species. Diascia growing zones vary depending on the species. For more information, see the descriptions below. To find your zone, click here: Zone Map.
Diascia barberae (Barber's Diascia, Twinspur)
This is commonly grown as an annual, but is technically a perennial. It grows best in USDA hardiness zones 8-11 or Sunset growing zones 5-10, 14-24 and H1. It forms a mat 10-12 inches tall and 20 inches wide with rose-pink blossoms. Varieties are outlined below:
This is commonly grown as an annual, but is technically a perennial. It grows best in USDA hardiness zones 8-11 or Sunset growing zones 5-10, 14-24 and H1. It forms a mat 10-12 inches tall and 20 inches wide with rose-pink blossoms. Varieties are outlined below:
'Blackthorn Apricot'
With apricot-colored flowers. |
'Darla'
This group of plants comes in many colors, and plants reach about |
'Fisher's Flora'
Grows in zones 7-9 and 14-24, and forms a mat 6 in. tall and 20 in. wide, with salmon-pink blossoms. |
'Ruby Field'
Gets 10 inches tall and 2 feet wide, with salmon-pink blossoms and a long bloom period. |
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Diascia fetcaniensis (Twinspur) This semi-evergreen perennial groundcover species grows best in USDA hardiness zones 8a-10b or Sunset growing zones 4-9 and 14-24; gets to 10 inches tall and 20 inches wide with rose-pink blooms. Cultivars include 'Daydream' (with loose racemes of deep pink flowers and a creeping, suckering habit to 10-15 inches tall) and 'African Queen' (with rich pink flowers with dark centers). |
Diascia spp. Hybrids (Hybrid Diascia, Hybrid Twinspur)
These plants grow best in USDA hardiness zones 8-11 or Sunset growing zones 4-9, 14-24 and H1. Unique hybrid cultivars are outlined below:
These plants grow best in USDA hardiness zones 8-11 or Sunset growing zones 4-9, 14-24 and H1. Unique hybrid cultivars are outlined below:
'Blackthorn Apricot'
With soft pink flowers. |
'Blue Bonnet'
Mauve-blue to lavender flowers; grows to a foot tall. |
'Coral Belle'
7-10 inches tall and 1.5 feet wide. Has coral pink flowers. |
'Emma'
Cold-hardy variety that grows to 2 feet tall and 4 feet wide. Flowers are pink-red. |
'Flirtation Orange'
Gets 8-12 inches tall and has orange blooms. |
'Flying Colors'
These get to 6-12 inches tall and flowers come in colors such as red, pink, apricot and coral. |
'Ice Pole'
Gets 1-14 inches tall and and 18 inches wide. Flowers are pure white. |
'Langthorn's Lavender'
Grows to 1 foot tall and has lavender flowers. |
'Little Charmer'
Pink flowers with dark red centers. 7-10 inches tall and 1.5 feet wide. |
'Red Ace'
7-10 inches tall and 1.5 feet wide. Red-rose flowers. |
'Red Start'
8 inches tall and 1 foot wide, with watermelon-red blooms. |
'Strawberry Sundae'
Deep pink flowers. 7-10 inches tall and 1.5 feet wide. |
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Diascia integerrima (Entire-Leaved Twinspur) This vigorous, evergreen perennial species grows best in USDA hardiness zones 5-9 or Sunset growing zones 2-9 and 14-24. Gets to 1.5 feet tall and 3-4 feet wide. Plants have a spreading, creeping habit, growing in width over time. Flowers form in loose upright spikes and are purple-pink. Popular variety 'Coral Canyon' (pictured) gets to 12-15 inches tall and 1.5 feet wide at maturity and has salmon-colored flowers. |
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Diascia rigescens (Stiff Twinspur, Twinspur, Bride's Saddle) This species of Diascia grows best in USDA hardiness zones 7-11 or Sunset growing zones 7-9 and 14-24 and gets to 1 foot tall and twice as wide. 6-8 inch tall spikes bear rich pink flowers. Old stems can be deadheaded to prolong bloom period and clean up appearance of these plants. These flowers are commonly grown in containers or hanging baskets. |
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Diascia vigilis (Twinspur, Elf Spur) This semi-evergreen species grows best in USDA hardiness zones 7-10 or Sunset growing zones 4-9 and 14-24 and reaches 20 inches tall and just a bit wider. Green leaves are fleshy and blooms are light pink. This species forms a hardy, fairly drought-tolerant small scale groundcover that grows into a mat over time. Varietal 'Jack Elliott' has pink blooms with yellow and maroon markings that are larger than the species. |
Caring for Diascia
Delicate Diascia plants do well in climates that have low humidity and temperatures, and will struggle during the warmest months of summer. These plants should be planted in early spring as soon as the last frost of the year has passed in a spot in the garden that receives full sun to partial shade. The delicate nature of these plants means that although they do love the sun, they will need some protection from the strongest light in the late afternoon when temperatures are the warmest. These flowers will bloom the best when they receive between 6 and 8 hours of sunlight each day. They grow in well-draining, fertile, slightly acidic (between 6.0 and 6.5.) soil. If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing. Dianella can be planted either in-ground or in containers. Apply a thick layer of mulch around the base of plantings to increase soil moisture retention, maintain soil temperatures, and suppress weed growth.
Water newly planted Dianella regularly as they establish a strong root system. At maturity, these plants are considered to be somewhat drought-tolerant and will get by on rainwater alone with supplemental waterings during the warmest times of the year. As a general rule of thumb, irrigate any time the top inch or two of soil feels dry to the touch. Yearly in springtime, apply a 2-inch layer of organic compost around the planting area to improve soil structure, drainage, and nutrient load. This feeding should be sufficient to provide these flowers with enough nutrients to get through their growth and flowering seasons with ease. Pruning is not necessary, but if any foliage is becoming unsightly, it can be removed at any time during the growing season. Diascia plants may die back in winter if planted in cool, wet soil. They can be sheared down after the bloom period passes in summer to encourage more new foliage to emerge and for a second fall bloom. Diascia flowers can be grown as annuals, pulled and composted at the end of the growing season, or short-lived perennials that can survive for a few years before needing to be replaced. These flowers will readily re-seed in the garden, providing volunteer seedlings indefinitely.
Water newly planted Dianella regularly as they establish a strong root system. At maturity, these plants are considered to be somewhat drought-tolerant and will get by on rainwater alone with supplemental waterings during the warmest times of the year. As a general rule of thumb, irrigate any time the top inch or two of soil feels dry to the touch. Yearly in springtime, apply a 2-inch layer of organic compost around the planting area to improve soil structure, drainage, and nutrient load. This feeding should be sufficient to provide these flowers with enough nutrients to get through their growth and flowering seasons with ease. Pruning is not necessary, but if any foliage is becoming unsightly, it can be removed at any time during the growing season. Diascia plants may die back in winter if planted in cool, wet soil. They can be sheared down after the bloom period passes in summer to encourage more new foliage to emerge and for a second fall bloom. Diascia flowers can be grown as annuals, pulled and composted at the end of the growing season, or short-lived perennials that can survive for a few years before needing to be replaced. These flowers will readily re-seed in the garden, providing volunteer seedlings indefinitely.
Propagation
Diascia can be propagated either by using cuttings or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your Diascia plants, follow the instructions below:
Propagating Diascia by Cutting
Propagating Diascia by Seed
Propagating Diascia by Cutting
- Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. A good substrate for propagation of cuttings is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
- In spring or early summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 3-4 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
- Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots.
- Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new flower.
Propagating Diascia by Seed
- Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. The best potting medium for seed germination is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
- Harvest your seeds. The seed heads on Dianthus plants are pretty easy to find, they're left behind after flowers have faded. Once they have dried out, you can harvest the seeds inside. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place the paper bag in a dry, cool, dark area. They will begin to split open and release the seeds contained inside, or they can be manually opened. Once seeds have been released, take them out of the bag and put them in a container so you can work with them.
- Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray on the soil surface and cover them with a light layer of soil. Water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 7 to 14 days from sowing.
- Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.
Problems and Pests
Diascia plants can have issues with the following pests and diseases in the landscape:
- Aphids
- White Flies
- Crown and Root Rot
Gallery
Diascia plants are wonderful in containers.
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Grow Diascia in mixed beds, where their foliage and flowers will fill in low, small gaps.
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In this informal garden, Diascia flowers jump out into the walkway.
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Diascia flowers resemble those of Snapdragon plants.
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They are commonly included in hanging baskets.
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Here, Diascia is planted alongside Lobelia, Sweet Alyssum, and Petunia in a multi-container arrangement.
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Videos
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How to care for Hybrid Diascia in the garden.
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Learn how to propagate these plants by taking cuttings.
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Resources
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Pages 286 - 287, Diascia
