Diascia (Twinspur) Growth and Care Guide
Diascia, commonly known as Twinspur, is a charming flowering plant prized for its delicate blooms that spill gracefully from containers and garden beds. In this Plant Guide, you’ll learn everything you need to know about growing and caring for Diascia successfully in your garden or containers. We cover ideal growing conditions, maintenance tips, best varieties, and much more.
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By: Reggie Meehan (10/25/2025) - Last Updated (2/16/2026)
Introduction To Diascia
Diascia, commonly known as Twinspur, has become one of my favorite cool season bloomers over the years. Native to South Africa and a member of the Scrophulariaceae family, it is known for its vibrant, tubular flowers and its naturally mounding to lightly trailing habit. The name Twinspur comes from the two small spurs that extend from the back of each bloom, a detail you really notice when you lean in close. I have always appreciated how airy and delicate the flowers look, even though the plant itself is surprisingly resilient. Older varieties tended to trail more loosely, but modern breeding has introduced compact, mounded, and even more upright forms that are much easier to design with.
In Northern climates, it can thrive in full sun with well drained soil, but here in the South I recommend part sun locations to help it handle our Summer heat. It shines in early Spring and again in Fall when temperatures are moderate and consistent. In our trials, we have found that performance always improves when nights are cool and days are mild. The blooms appear generously over that period, creating a lively wash of color that feels effortless. Whether tucked into a mixed container or planted along a bright border, Diascia adds refinement, movement, and dependable seasonal charm.
With my love of bold colors, it was of course Diascia 'Darla® Red' that I first planted as an accent plant in my part-sun containers. I’ll be honest, my plants suffered from chronic abuse that year due to health reasons. I knew that Diascia would not be showy in the summer, but the other plants in my part-sun planter flourished. Then, come October, my showy Summer plants receded and my Diascia was again at the forefront, blooming and showing off. Again, I am reminded that Diascia is a cool season bloomer and we all should treat it like that. Incorporating cool season bloomers in pots will ensure that you have longevity of blooms till first frost, after the showy plants have spent themselves to death.
Characteristics of Diascia (Twinspur)
Diascia has earned a permanent place in my lineup because it delivers color without demanding constant attention. I have grown it in tight patio containers, wide landscape beds, and everything in between, and it adapts beautifully. The blooms are vibrant but soft, never harsh, and the foliage stays fresh looking when temperatures cooperate. For gardeners just getting started, it is forgiving and easy to manage. For more experienced designers, it offers texture and movement that can elevate an entire planting scheme.
Size and Growth Habit
Most Diascia varieties stay compact, typically reaching about 6 to 12 inches tall. Depending on the selection, they can spread up to 18 or even 24 inches wide, forming either a tight mound or a softer trailing shape. I like that range because it gives me options without introducing unpredictability. The mounding types are especially useful at the front of borders where you want a clean, defined edge. The trailing selections shine in containers, spilling gently over the rim without becoming wild or unruly.
In the landscape, that habit really determines placement. Mounded forms create structure and rhythm in beds, while trailing types soften hard edges in window boxes and hanging baskets. No matter which form you choose, Diascia maintains a naturally tidy appearance that makes the whole planting look thoughtful and well planned.
Leaves and Flowers
The foliage of Diascia is one of those details people do not always notice at first, but it makes a big difference in overall performance. The leaves are small, bright green, and oval shaped, forming a dense, tidy base that supports the blooms beautifully. I like how closely spaced they are along the stems because it gives the plant a full appearance even before it comes into heavy flower. There is a slight gloss to the foliage that keeps it looking fresh rather than dull. Even between bloom cycles, the plant still looks healthy and intentional. You don't get the open gaps or stretched out stems that some flowering annuals develop as the season progresses.
The flowers are what truly set Diascia apart. Each bloom is tubular with two distinct spurs extending from the back, which is how it earned the name Twinspur. Those spurs actually hold nectar, which is why bees are such frequent visitors in our trials. I have often noticed pollinators working the flowers steadily during cool, sunny mornings. The color range is broad, from coral and soft pinks to deeper rose, orange, white, and even purple tones. The blooms rise in abundance above the foliage, creating a soft but vibrant canopy of color.
Is Diascia Annual or Perennial?
Diascia is typically treated as an annual, providing a burst of colorful flowers from Spring to Fall before being affected by frost. Diascia can be perennial in USDA Hardiness Zones 9 and 10, flourishing in regions with mild, frost-free winters where it can grow and bloom year-round. For gardeners in colder zones, Diascia can be overwintered indoors, allowing the plants to return for another growing season, or simply replanted each Spring.
Best Varieties of Diascia
Not a single variety of Diascia has ever received a trial rating above 4.8. This is probably because Diascia is not designed to thrive in full sun and does best in cooler weather. Only limited Diascia varieties will continue to bloom in the throes of Summer, and usually this is only if they are placed in part sun environments. Thus, the standards for judging Diascia based on blooms all season long in the full hot sun will never afford us the data that fairly judge Diascia, which is a cool season bloomer. For that reason, when rating the best Diascia, we used factors including internet searches, popularity with growers, and other factors discussed below.
Darla® Series
The Darla® Series by Syngenta Flowers simply rules. It is a big mass of flowers that leads to an even greater mass of tangled flowers. It is the most popular series, primarily because it has been around for forever and thus is the variety with which consumers are most familiar. We carry the Light Pink, Rose, and White varieties.
The Darla series are characterized by sprawling plants that reach about 10–12 inches tall and 12–24 inches wide. It thrives in full sun to part sun. However, it provides only cool season color, meaning early to late spring and again in the fall. Flowering may pause during extreme summer heat, then resume as temperatures cool. All colors of the Darla series are equally popular.
Coral Canyon
This hardy perennial variety (advertised to be cold hardy to Zone 5, but other documents say Zone 7) features coral-pink flowers with an upright and trailing habit, with blooms that are supposed to last all summer. Coral Canyon Diascia is a High Country Gardens introduction, they suggest it “is one of the best new perennial introductions of the past 25 years.” We trial tested it in 2025 in a part sun environment, appropriate for hot and humid Southern summers. It did not bloom all summer and it was more of a trailer than upright. That said, it was gorgeous when it was blooming and as a perennial, its foliage remained attractive throughout the summer. Can’t wait to trial it again next year.
Piccadilly ™ Series
The Piccadilly series from Selecta One, is a mounded series growing 6–10 inches tall and 8–10 inches wide. It prefers part sun and is prized for its large flowers on short stems, early bloom, and cool-season performance. Piccadilly™ shines in early spring and fall, but may decline or stop blooming in midsummer heat, especially in southern zones. Piccadilly™ Pink stands out as the top seller—outselling other individual colors by a factor of four. Its popularity is undeniable, yet the reason behind its appeal remains a mystery. I’m genuinely excited to trial it myself and uncover what makes this particular pink so irresistible.
Trinity™ Series
The Trinity™ series, developed by Danziger, offers upright to mounded plants approximately 12–14 inches tall and 12–16 inches wide. It performs best in full sun and is known for its large flowers and strong branching. Trinity™ cultivars bloom from Spring through Summer, with better heat tolerance than older types, though some fade may occur in peak heat. The Trinity Sunset variety is the most popular, selling double the other colors. Note that in the South, I’d try this in afternoon shade for best performance.
Juliet™ Series
The Juliet™ series, bred by Ball FloraPlant, features compact upright plants about 6–8 inches tall and 4–6 inches wide. It thrives in full sun to part sun, and blooms from early Spring through Autumn. In hot climates, flowering may slow or stall in Summer. This series makes a great well-mannered filler.
Sundiascia®
Sundiascia® is a completely new form of Diascia with a unique, upright habit and tall sturdy flower spikes. This variety is more heat tolerant with an extended bloom time. A great thriller component as it looks a lot like angelonia. Although this plant does not have the popularity among growers or consumers yet, it receives an honorable mention because we all want another upright flowering plant to meet our filler needs. Can’t wait to trial test this.
How to Grow and Care for Diascia
Diascia is one of those plants I recommend often because it rewards you generously without demanding constant attention. When planted in the right spot and given simple, consistent care, it will provide steady color through the cool season and often beyond. I have grown it in containers, raised beds, and open landscape plantings, and the fundamentals are always the same. Give it drainage, give it light, and avoid overwatering. When those basics are covered, it tends to perform beautifully. Below is how I guide customers to grow it successfully based on what we have seen in our own trials.
Planting Diascia
Plant annual Diascia in Spring after all danger of frost has passed, as most varieties will not tolerate a hard freeze. Choose a sunny location with well draining soil, though in the South I strongly recommend part sun with afternoon protection to prevent heat stress. Space plants about 12 to 18 inches apart so they have room to mound or trail naturally without crowding. In containers, always use a lightweight potting mix that drains freely because soggy roots are the quickest way to lose this plant.
For perennial types such as Coral Canyon, timing depends on your zone. In Zones 7 and 8, Fall planting allows roots to establish during Winter dormancy. In Zones 5 and 6, Spring planting gives the plant a longer runway to establish before extreme cold arrives.
Sunlight Requirements
Diascia performs best with at least six hours of direct sunlight per day, especially in cooler climates. In Northern regions, full sun typically produces the heaviest bloom set. Here in the South, however, intense afternoon sun can shorten its bloom window. I often recommend morning sun with afternoon shade for Zones 7 and above. That balance helps preserve foliage quality and encourages steadier flowering. Too much shade will reduce bloom production and may cause stretching. Proper placement is one of the most important factors in keeping it attractive all season.
Soil Requirements
Well draining soil is absolutely essential. Diascia prefers soil enriched with organic matter and a slightly acidic to neutral pH between 6.0 and 7.0. Heavy clay or consistently wet conditions will almost always lead to root rot. If planting in clay based soils, amend generously with compost or plant in raised beds. Good drainage supports stronger root systems and more consistent flowering. In containers, avoid heavy mixes that retain too much moisture. Healthy roots equal healthy tops with this plant.
Watering Needs
Keep soil consistently moist during establishment, but never waterlogged. Once established, Diascia tolerates moderate dryness better than saturated soil. During hot or windy spells, increase watering frequency to prevent wilting. Container grown plants will require more frequent checks because pots dry out faster than garden beds. Always allow the top inch of soil to dry slightly before watering again. Overwatering is far more damaging than slightly underwatering this plant.
Fertilizer Needs
Feed Diascia with a balanced, water soluble fertilizer every four to six weeks during active growth. A moderate, consistent feeding schedule supports continuous blooming without forcing excessive foliage. Too much fertilizer can result in lush green growth but fewer flowers. I prefer steady, light feeding rather than heavy doses. In containers, nutrients leach out more quickly, so regular feeding is especially helpful. Healthy nutrition keeps the plant compact and productive.
Pruning and Maintenance
Regular maintenance keeps diascia performing at its best. Trim spent blooms to encourage fresh flowering and prevent the plant from becoming covered in old stalks. One technique I often suggest is pinching back one stem every few weeks rather than cutting the entire plant at once. This keeps blooms cycling without leaving the plant temporarily bare. If the plant becomes leggy or tired, a more significant trim before Summer heat can stimulate fresh growth. Perennial varieties can be cut back to the ground at the end of the season. If annual types are not cut back periodically, they may slow flowering considerably.
Overwintering
In USDA Zones 9–10, annual Diascia can survive mild winters with minimal protection, such as mulch around the base. For colder climates, move container-grown Diascia indoors to a bright, frost-free location before the first frost. Most commonly found Diascia are p. But for the Darla series (except the and for Coral Canyon Diascia that are not patented, you can propagate cuttings in late summer to keep the plant going indoors until the following spring.
Note that Coral Canyon Diascia is supposedly winter hardy to Zone 5, though other data suggest only to Zone 7. Coral Canyon is a relatively new Diascia variety so only time will tell about its hardiness. Sorry.
Common Pests
Diascia is generally low in pest pressure but may occasionally attract aphids, thrips, or whiteflies. Inspect plants regularly, especially the undersides of leaves where pests tend to hide. Insecticidal soap works well for aphids, neem oil can help manage mites, and spinosad is effective for thrips. Good airflow reduces pest issues significantly. When spraying, always coat the underside of foliage thoroughly for effective control. If temperatures exceed 90 degrees Fahrenheit, apply neem oil in the evening and rinse lightly the next morning to prevent leaf scorch.
Common Diseases
Root rot is the most common issue and is almost always tied to poor drainage or overwatering. Planting in well draining soil is the best prevention. Fungal problems are uncommon when airflow is adequate. If fungal disease appears, treat promptly with an appropriate fungicide. Prevention through proper placement is far easier than correction later.
Common Mistakes
Overwatering remains the most frequent mistake I see. Planting in too much shade is another common issue, leading to reduced blooms and stretched growth. Neglecting to remove spent flower stalks can cause the plant to slow its bloom cycle. Failing to provide afternoon shade in hotter Southern zones can also shorten performance. Small adjustments in placement and maintenance make a big difference with this plant.
Common Misconceptions
Some gardeners believe Diascia does not bloom all season, and in certain climates or poor placements, that can be true. However, in Zones 7 and warmer, placing it in afternoon shade often extends its bloom window significantly. Modern breeding continues to improve heat tolerance and overall performance. Proper deadheading in late Spring can also help encourage continued flowering into Summer. Others assume Twinspur is difficult in containers, yet it thrives in pots when drainage is excellent and watering is consistent. While tender in cold climates, it can often be overwintered indoors with planning.
Using Diascia in the Garden
Diascia is the type of plant that quietly elevates whatever space you put it in. I have used it in formal beds, casual cottage borders, and simple porch containers, and it adapts beautifully every time. Its fine texture and steady bloom make it easy to blend into almost any design style. Whether you are aiming for something soft and romantic or bright and energetic, it plays well with others.
Hanging Baskets and Containers
In containers and hanging baskets, Diascia really shows off. Trailing selections spill gently over the rim, softening the hard edge of a pot without becoming wild or tangled. I love how the flowers create a light, airy cascade rather than a heavy curtain of foliage. It works beautifully on patios, balconies, and front porches where you want steady color at eye level.
Pairing it with complementary plants like Lobelia or Petunias helix adds depth and contrast, especially when you mix upright, trailing, and mounding forms together. Because Diascia stays compact and blooms prolifically, it thrives in smaller containers where space is limited. I often recommend it for urban gardens or tight corners where larger plants would overwhelm the design. With good drainage and consistent watering, it keeps containers looking fresh and intentional from early Spring well into Fall.
Borders and Edging
Diascia is one of my favorite plants for defining borders and softening pathways without creating extra work. In our trials, perennial selections like Diascia ‘Coral Canyon®’ have proven especially useful for forming clean, low edges that stay neat through the cool season. I like using these mounding types along brick or stone walkways because they soften the hard lines without spilling too far into the path.
The steady bloom cycle keeps borders looking intentional rather than patchy. Compared to higher maintenance edging plants, Diascia holds its shape with far less trimming. The flowers add a cheerful wash of color that draws the eye down a pathway. It is a simple way to add polish and structure without complicating the planting plan.
Rock Gardens
In rock gardens, perennial Diascia really finds its stride. It prefers well drained soil and does not tolerate heavy, soggy conditions, which makes rocky settings ideal. I often pair it with drought tolerant companions like Sedum for a cohesive look that handles dry spells gracefully. The fine texture of Diascia contrasts nicely with thicker, succulent foliage. Its bright blooms break up the gray and stone tones that can sometimes feel flat in rock gardens.
Even a small pocket of coral or pink can completely change the mood of a rocky bed. Because it stays compact, it fits neatly between stones without overwhelming them. When planted thoughtfully, it adds life, color, and softness to spaces that might otherwise feel harsh or rigid.
Diascia Delivers Cascading Color
Looking to grow Diascia in your garden this season? At Garden Delivery, we carry top performing Diascia varieties selected for their delicate, snapdragon like blooms and refined, mounding to lightly trailing habit. These cool season favorites truly shine in early Spring and again in Fall, delivering soft, airy color when temperatures are mild. Whether you are planting hanging baskets, patio containers, or the front edge of a garden border, Diascia adds texture and movement without overwhelming nearby plants.
Available in shades of coral, pink, apricot, rose, and crisp white, our selections are chosen specifically for strong bloom power and dependable garden performance. We focus on varieties that stay compact, branch well, and maintain a polished look with minimal maintenance. When placed properly in well draining soil and given morning sun with afternoon protection in the South, Diascia will reward you with steady, cheerful blooms. If you want effortless cool season beauty that feels light and romantic, Diascia is a wonderful place to start.