Can Zinnias Grow in Shade? A Guide to Growing These Bright Flowers in Low Light

Zinnias are known for their vibrant, colorful blooms that add cheer to gardens during the hot summer months. With varieties in just about every color except blue it’s no wonder they are so popular. But most gardeners know that these annuals typically thrive in full sun. So what if you have mostly shady areas in your landscape? Can zinnias grow in shade?

The short answer is yes, zinnias can grow in shade but with some caveats. While they definitely prefer full sun, they can tolerate partial shade fairly well Let’s take a closer look at how much sun zinnias need, which varieties work best in shade, and tips for successfully growing these flowers in low light conditions

How Much Sunlight Do Zinnias Need?

Most zinnias require full sun, which means at least 6 hours of direct sunlight per day. Exposure to sunlight triggers the production of blooms. With insufficient light, you’ll end up with sparse flowering and leggy, stretched out plants trying to reach for the sun.

While full sun is best, there are some varieties that can manage with 3-6 hours of sun, making them suitable for partial shade conditions. Filtered sunlight that passes through trees is better than heavier shade cast by buildings or fences. Morning sun is preferable to afternoon sun.

• Full sun (6+ hours direct sun) is optimal
• Partial shade (3-6 hours) can work for some varieties
• Morning sun is better than afternoon
• Heavy shade won’t allow for good growth

If you only have a shady spot with less than 3 hours of sun per day, it’s best to choose shade-loving flowers other than zinnias.

Best Zinnia Varieties for Partially Shady Gardens

When choosing zinnia varieties to grow in partial shade, look for ones labeled as shade tolerant on the seed packet. Dwarf and compact types will flower more readily in low light than taller varieties.

Here are some top picks:

• Zahara zinnias – This compact series blooms prolifically in shades of cherry, orange, yellow, white, scarlet, and mix. Grows 12-18 inches tall.

• Dreamland zinnias – Dense, double blooms on dwarf 10-inch plants. Good choices are ‘Rose Bonbon’ and ‘Coral Reef’ mixes.

• Magellan zinnias – Semi-dwarf at 16-20 inches with large, vivid blooms in solids and bicolors. Try ‘Cherry’ and ‘Orange.’

• Profusion zinnias – Extremely disease resistant and heat tolerant. Grows 12-20 inches tall with 2-inch single or semi-double flowers.

• Starlight zinnias – Dwarf 10-inch plants with unique bicolor flowers. ‘Rose Bonbon’ has pink and white blooms.

• State Fair zinnias – An heirloom variety that produces giant dahlia-like blooms on 30-inch plants. More shade tolerant than most large types.

Check seed packets for specifics on sun requirements to determine if a variety can work in partial shade. Stick to ones that say “part sun,” “partial shade,” or give a range of sun hours.

Growing Tips for Zinnias in Shade

If you only have a partly shady spot, follow these tips to help your zinnias thrive:

• Give them the sunniest area possible – Place them along the edges of planting beds or in open areas of your yard. Morning sun is ideal.

• Use light-reflecting mulch – Mulch beds with light colors like white stone or sand rather than dark bark. This will reflect sunlight up to the plants.

• Water carefully – Overwatering leads to root rot and disease in low light. Allow soil to dry between waterings.

• Pinch back plants – Pinching off top growth encourages bushier, compact plants that bloom better in shade.

• Fertilize lightly – Too much fertilizer results in leggy growth needing more sun. Use half strength or less.

• Plant close together – Dense spacing means they support each other and bloom more profusely. Space 6-12 inches apart depending on variety.

• Add annuals for full sun – Partner sun-loving annuals like marigolds, petunias or cosmos nearby to brighten the area.

With attention to choosing the right varieties and following these growing tips, you can enjoy zinnias even in partly shady garden beds. Observe how your plants do over the season and make notes on which ones flower best in shade to grow again next year.

Do Zinnias Flower in Heavy Shade?

Zinnias generally won’t bloom well in heavy shade, meaning less than 3 hours of direct sunlight per day. Without sufficient light, the plants become tall and leggy as they reach for the sun, with few flowers. Heavy shade is cast by fences, buildings, and trees with dense, overlapped canopies that block most direct sunlight.

Some gardeners have success getting zinnias to bloom in heavy shade by planting dwarf varieties like Dreamland or Starlight. Combining them with shade tolerant annuals like impatiens, begonias and coleus can perk them up. But in most cases, it’s best to look for alternative shade flowers.

Best Flowers for Heavy Shade Gardens

Full shade with minimal sunlight rules out most flowering annuals like zinnias. Instead, plant these beauties that thrive with 2-3 hours of filtered sun or less:

Annuals:

• Begonias
• Coleus
• Impatiens
• Fuchsias
• Browallia

Perennials:

• Astilbe
• Coral bells
• Ferns
• Hellebores
• Hostas
• Lungwort
• Solomon’s seal

Bulbs:

• Caladiums
• Calla lilies

Focus on foliage plants with brightly colored or variegated leaves. Add color with shade-loving annuals in pots. For flowers, choose low-growing perennials and early spring bulbs that bloom before trees leaf out.

Special Considerations for Zinnias in Shade

Growing zinnias in shade presents some additional challenges you’ll need to stay on top of:

• Monitor for powdery mildew which thrives in low light and humidity. Provide good air circulation and avoid wetting foliage.

• Watch for stretching and legginess which indicates insufficient sunlight. Pinch back and move to the brightest area possible.

• Expect to see smaller blooms since less light means less energy for the plant to produce flowers. Focus on compact varieties.

• Be prepared to provide support for tall varieties that start to flop over due to inadequate sunlight. Use stakes, cages, or trellises.

• Deadhead frequently to encourage more blooms to form. Removing spent flowers signals the plant to keep flowering.

• Plant extras since germination rates are lower in shade. Overseed beds and thin later.

• Fertilize very lightly to avoid leggy growth. Too much nitrogen causes weak stems needing more sun.

With extra attention in these areas, you can maximize your shade zinnia’s performance. Observe plants daily and adjust care as needed.

Example Plants That Do Well in Shade

To give you an idea of how some specific zinnia varieties fare in shady conditions, here are a few real-world examples:

• Zahara Starlight Rose grew to 12 inches tall and bloomed decently with about 4 hours of morning sunlight filtered through trees.

• A gardener had luck with Magellan Cherries ‘N Wine in mostly shade, but the plants stretched to 4 feet and required frequent trimming back and staking.

• Profusion Orange planted in bright shade under a canopy of honey locust trees grew bushy 10-inch plants covered in vivid orange single blooms.

• Dreamland Rose Bon Bon achieved a height of 8 inches with good flowering in a north-facing courtyard that got about an hour of late afternoon sun.

As you can see, results vary quite a bit. Monitor your plants and adjust your approach until you find the right balance for your specific conditions.

Final Tips for Growing Zinnias in Shade

• Stick with compact, dwarf varieties under 12 inches tall.

• Locate in the brightest area possible, with morning sun if available.

• Use light colored mulch to reflect more light.

• Pinch plants back frequently to encourage bushy form.

• Water carefully, allowing soil to dry out between waterings.

• Partner with annuals that tolerate shade for more color.

• Be prepared to provide support for floppy plants.

• Deadhead regularly to promote more blooms.

• Watch for diseases like powdery mildew that thrive in shade.

• Don’t fertilize heavily to avoid leggy, weak growth.

With the right approach, you can enjoy the beauty of zinnias even in partially shaded garden beds and borders. Just focus on compact types promoted as shade or part sun varieties. Monitor their progress and make adjustments as needed. While they may not flower as prolifically as those grown in full sun, they’ll give you plenty of bright color in low light situations.