If you’re planning your garden beds or containers, a common question is how tall do impatiens grow. Knowing their maximum height and spread helps you place them perfectly for a stunning display all season long.
These popular shade lovers are known for their prolific blooms and easy care. But their size can vary quite a bit depending on the type you choose and how you grow them.
Let’s look at what you can expect from these colorful plants.
How Tall Do Impatiens Grow
Most common bedding impatiens, like the classic Impatiens walleriana, typically reach a height of 6 to 24 inches. Their spread is usually similar, creating a mounded, bushy shape.
The maximum height for standard varieties in ideal conditions is about 2 feet. However, newer hybrids and different species have expanded this range significantly.
Their growth habit is generally compact and dense. They fill in spaces quickly with their bright green foliage and many flowers.
Factors That Influence Impatiens Size
Several key elements determine how big your impatiens will get. It’s not just about the seed packet label.
Understanding these helps you manage their growth.
- Variety or Cultivar: This is the biggest factor. Dwarf types stay small, while vigorous hybrids can get quite tall.
- Sunlight: Impatiens prefer partial to full shade. In too much sun, they may stay shorter and stressed. In deep shade, they might become leggy reaching for light.
- Soil Quality: Rich, well-draining soil packed with organic matter fuels much larger growth. Poor soil stunts them.
- Watering: Consistent moisture is crucial. Drought stress will severely limit their size and health.
- Spacing: Plants placed too close together compete and grow taller but thinner. Proper spacing allows for full, mounded development.
- Fertilization: A regular feeding schedule with a balanced fertilizer promotes robust growth and bigger plants.
Popular Types and Their Typical Sizes
Not all impatiens are created equal. Here’s a breakdown of common groups.
1. Traditional Bedding Impatiens (Impatiens walleriana)
These are the classic shade annuals. They were hit by downy mildew but many resistant varieties are now available.
- Height: 8 to 24 inches
- Spread: 10 to 24 inches
- Note: The ‘Super Elfin’ series stays compact at 8-10 inches, while ‘Infinity’ can reach up to 2 feet.
2. New Guinea Impatiens (Impatiens hawkeri)
These have larger, showier leaves and flowers and tolerate a bit more sun.
- Height: 12 to 24 inches
- Spread: 12 to 24 inches
- Note: They tend to have a more upright habit. Some, like the ‘SunStanding’ series, are bred for even better sun tolerance.
3. Impatiens ‘Bounce’ & ‘Big Bounce’ Series
These are mildew-resistant hybrids with a vigorous, spreading habit.
- Height: 14 to 22 inches
- Spread: 14 to 24 inches
- Note: They live up to their name, “bouncing” back quickly from heat or wilting.
4. Impatiens ‘SunPatiens’ Series
These are the giants of the impatiens world. They thrive in full sun to part shade and grow remarkably large.
- Height: 24 to 48 inches
- Spread: 24 to 36 inches
- Note: They can truly become large, shrub-like annuals in a single season, offering maximum impact.
How to Control and Encourage Growth
You have more control over your impatiens size than you might think. Here’s how to manage it.
To Encourage Maximum, Healthy Growth:
- Plant in Rich Soil: Amend beds with several inches of compost or aged manure before planting.
- Water Deeply and Regularly: Keep the soil consistently moist, but not soggy. Drip irrigation is ideal.
- Fertilize Regularly: Use a slow-release fertilizer at planting and supplement every 2-4 weeks with a water-soluble bloom fertilizer.
- Provide Ideal Light: For most types, aim for 2-4 hours of morning sun or dappled all-day light.
To Keep Impatiens Compact and Bushy:
- Pinch Early: When young plants are a few inches tall, pinch off the top set of leaves. This encourages side branching.
- Prune Leggy Stems: Don’t be afraid to cut back long stems by one-third mid-season. They’ll branch out below the cut.
- Avoid Overcrowding: Follow spacing recommendations on the tag. For large varieties like SunPatiens, 2 feet apart is often needed.
- Limit Nitrogen: If plants are leafy but not blooming, ease up on high-nitrogen fertilizers which can cause excessive, weak growth.
Common Problems That Affect Size
Sometimes impatiens don’t reach there expected size due to issues. Here’s what to watch for.
- Downy Mildew: Causes stunting, leaf drop, and eventual collapse. Plant only resistant varieties.
- Insect Pests: Aphids and spider mites can weaken plants. Treat with insecticidal soap or a strong water spray.
- Water Stress: Wilting and dry soil will pause growth. Consistent moisture is non-negotiable for good size.
- Poor Soil: Hard, clayey, or nutrient-poor soil just won’t support large, healthy plants. Always amend it.
Design Tips Using Their Height and Spread
Use their growth habits to your advantage in the garden.
- Edging and Borders: Use compact varieties (6-12 inches) along walkways or at the front of beds.
- Mass Planting: Medium-sized varieties (12-18 inches) create a stunning carpet of color. Plant in odd-numbered groups for best effect.
- Container Thrillers: Tall SunPatiens make a perfect centerpiece for large pots, with spillers like sweet potato vine around the edges.
- Filling Gaps: Their quick, mounding spread is ideal for filling empty spots in shaded garden areas under trees.
FAQ: Impatiens Height and Spread
What is the tallest impatiens variety?
The Impatiens ‘SunPatiens Vigorous’ series holds the record, easily reaching 3 to 4 feet in height and spread under optimal conditions.
Can impatiens get too tall and leggy?
Yes, especially in too much shade. They stretch for light. Pinch them back early and regularly to maintain a bushy, compact form. If they’re already leggy, a mid-season trim can help.
How wide do impatiens plants spread?
Spread is usually equal too or slightly greater than height for mounding types. A plant labeled as 14 inches tall will often spread 16-18 inches wide. Always check the specific variety’s tag.
Do impatiens grow back every year?
In most climates, impatiens are grown as annuals and won’t survive frost. In tropical zones, they can be perennial. They also often self-seed mildly in perfect conditions.
How fast do impatiens grow?
From a small transplant, impatiens grow quite quickly in warm weather with adequate water. They can reach near their full size within 5-8 weeks after planting in the garden.
Understanding how tall impatiens grow and what affects there size empowers you to make the best choices for your space. Whether you need a low border or a towering container centerpiece, there’s an impatiens variety that fits the bill. With the right care, you can enjoy their cheerful blooms at just the size you want all summer long.