Why Are My Marigolds Growing So Darn Tall?

Marigolds are a beloved flower known for their bright, cheerful blooms that come in shades of yellow, orange, red and more. Thesecompact plants are extremely popular in home gardens because they’re easy to grow, bloom all season long and can brighten up any landscape.

However, some gardeners end up with marigolds that grow much taller and lankier than expected. If your marigolds have bolted skyward this year, you may be wondering — why are my marigolds growing so tall?

There are a few key reasons why marigold plants can end up stretching themselves a lot taller than their typical height Read on to find out the main factors that cause leggy marigold growth, along with tips to troubleshoot oversized plants

Genetics Play a Role

One of the most obvious reasons why some marigolds grow quite tall is genetics. There are countless marigold varieties out there, and they naturally vary quite a bit in their size bloom colors and growth habits.

Some marigold species and cultivars are simply genetically predisposed to taller heights Here are a few examples

• African marigolds (Tagetes erecta) are known for their large, pom pom-like flower heads. Most varieties grow over 2 feet tall.

• French marigolds (Tagetes patula) are more compact, typically reaching 6 to 18 inches tall. However, some French marigold varieties can grow up to 3 feet tall if conditions are ideal.

• Signet marigolds (Tagetes tenuifolia) are the smallest type, with most varieties maturing around 1 foot tall. But even these can get lanky and exceed 12 inches.

So if you planted a variety labeled as “tall” or you’re growing large-flowered African marigolds, genetics could very well be the reason for the impressive vertical growth.

Too Much Fertilizer Feeds Leggy Growth

Giving marigolds too much fertilizer can also cause them to stretch their stems and grow much taller than normal. This is especially true if using fertilizers that are high in nitrogen.

Nitrogen is key for promoting leafy growth and vigor. But apply too much, and plants focus their energy on rapidly producing foliage and tall stems rather than flowers.

Organic fertilizers like compost and manure release nitrogen more moderately over time. But chemical fertilizers can provide a sudden nitrogen jolt that spurs bolting if overapplied.

Follow fertilizer labels closely and avoid overfeeding marigolds. Test your soil and only amend with more nitrogen if a test confirms it’s lacking.

Insufficient Sunlight Triggers Stretching

Marigolds thrive best in full sun — at least 6 hours of direct sunlight per day. Without enough light exposure, the plants can start stretching and etiolating as they desperately try reaching for more sunshine.

Factors like too much shade from trees, buildings or other plants can limit the amount of sun marigolds receive. Overcrowding plants together can also create competition for sunlight.

If your marigolds aren’t getting sufficient sun access, they’ll start climbing skyward. Try relocating plants to the sunniest part of your garden for stockier growth.

Spacing Issues Cause Crowding Stress

On the flip side, planting marigolds too close together can also trigger leggy growth. Crowding puts plants under stress as they compete for resources like light, water and nutrients.

To reach the sunlight above neighboring plants, crowded marigolds will bolt upward. Nearby plants also limit air circulation, which can further stimulate stretching.

Carefully follow marigold spacing guidelines on seed packets or plant tags. As a rule of thumb, leave 6 to 12 inches between small French marigolds and up to 2 feet between larger African marigold varieties.

Excess Moisture Prompts Vertical Growth

Proper watering is essential for healthy marigolds. But overwatering or heavy rains can lead to overly tall plants with sparse flowers.

Excess moisture dissolves soil nutrients, especially nitrogen, making them readily available for plant uptake. Coupled with soggy soil that limits oxygen flow to roots, this nitrogen abundance spurs weak, leggy growth.

Allow soil to partially dry out between waterings. Improve drainage in overly wet gardens. Provide shelter from heavy rainfalls. This encourages stocky, compact marigold growth.

Cool Weather Limits Proper Growth

Marigolds thrive in warm weather. But cool temperatures early in the growing season can stunt proper development. This leads to taller, weaker plants as the marigolds try to outpace the weather.

Exposure to cold snaps or chilly nights triggers marigolds to enter survival mode. They’ll focus energy on vertical growth as they try to keep their foliage and blooms away from frost risk at soil level.

Wait until all danger of frost has passed before planting marigolds in spring. Provide row cover protection if cold temperatures are forecasted after plants are established.

How to Fix Leggy Marigold Plants

If your marigolds are already stretching their stems sky high, don’t despair. Here are some tips to help coral gangly plants:

• Pinch or trim back top growth to encourage bushiness over height. Remove spent flowers to promote reblooming.

• Stake tall plants to provide needed support and prevent flopping. Use stakes and plant velcro ties.

• Fertilize lightly with lower nitrogen formulas, if needed, to limit foliar growth.

• Water carefully and improve drainage if soil is chronically moist. Allow soil to dry between waterings.

• If possible, move plants to a sunnier location for the remainder of the growing season.

• Space marigolds properly to prevent crowding and competition between plants.

• Choose shorter varieties if replanting for next year’s garden.

By troubleshooting the root causes of leggy growth, avoiding overfertilization, and providing proper sunlight and spacing, you’ll be rewarded with beautifully compact and floriferous marigolds all season long. Act quickly at the first signs of stretching, and you can get those towering marigolds back under control.