Geranium in Zone 6B — Great Plains

Geraniums are a classic choice for Plains gardeners, bringing vibrant color to containers and garden beds all summer long. Their ability to tolerate our intense sunshine, combined with relatively low disease pressure, makes them a rewarding flower to grow here. Plus, they attract pollinators, adding extra life to your garden.

Our Great Plains weather can be unpredictable, with extreme temperature swings and occasional hail. But by starting your geraniums at the right time and providing consistent care, you can enjoy their beauty throughout our approximately 198-day growing season.

Starting geraniums from seed indoors is possible, but be warned: they're slow growers. If you're up for a challenge, starting seeds indoors from late January through mid-February, about 12 weeks before you plan to transplant, will give them a head start.

Use seed trays with a good seed-starting mix. Keep the soil consistently moist, using bottom watering to avoid disturbing the tiny seeds. Provide warmth and plenty of light, and remember that our Plains springs can bring unexpected cold snaps, so keep an eye on the forecast.

The ideal time to transplant your geraniums outdoors is late April through late May. Before transplanting, harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to our variable spring weather and strong winds.

Plant them 10-12 inches apart in well-draining soil. Be aware that geraniums are very slow from seed, so buying starts from a local nursery might be the easiest way to enjoy them in your garden.

Geraniums need moderate watering, but they definitely aren't drought-tolerant. In our hot Plains summers, you'll need to pay close attention to their moisture levels. Let the soil dry slightly between waterings, as overwatering can lead to stem rot.

During the heat of summer, especially when temperatures climb into the 90s, check the soil moisture every few days. Stick your finger about two inches deep – if it feels dry, it's time to water. Aim for about an inch of water per week, watering at the base of the plant to avoid getting the foliage wet. Given our low-to-moderate humidity, overhead watering isn't as risky as in more humid climates, but it's still best to water at the base to prevent fungal diseases.

Signs of underwatering include wilting leaves and dry, cracked soil. Overwatering can cause yellowing leaves and mushy stems. A layer of mulch around the base of your geraniums can help retain moisture and regulate soil temperature, especially during our extreme temperature swings.

Deadheading is key to keeping your geraniums blooming all season long. Simply pinch off spent flower clusters as soon as they fade. This encourages the plant to produce more flowers instead of putting energy into seed production.

Throughout the season, pinch back any leggy stems to encourage bushier growth. As the first frost approaches in late October, you can bring your geraniums indoors to overwinter them, or simply let them die back naturally.

Geraniums are grown for their beautiful flowers, so your "harvest" is simply enjoying their blooms from early July through late August. Deadhead regularly to keep the plants looking tidy and to encourage continuous flowering.

As the flowers fade, gently remove them from the plant, being careful not to damage the surrounding foliage. This encourages the plant to keep producing new blooms. As the end of the season approaches and the first frost threatens in late October, you can take cuttings to propagate new plants indoors, or simply enjoy the last blooms before the frost arrives.

Here are some common problems you might encounter growing geraniums in the Great Plains:

Botrytis Blight

• What it looks like: Gray mold on leaves and flowers, especially during periods of cool, wet weather.
• What causes it: A fungal disease that thrives in humid conditions and poor air circulation. While we often have low humidity, periods of rainfall can trigger this.
• How to fix/prevent it: Remove infected plant parts promptly. Improve air circulation by spacing plants properly and pruning to open up the canopy. Avoid overhead watering.

Geranium Budworm

• What it looks like: Holes in buds and flowers, chewed leaves, and small green caterpillars.
• What causes it: These caterpillars feed on geranium buds and flowers.
• How to fix/prevent it: Handpick caterpillars when you see them. Use Bacillus thuringiensis (Bt) as a biological control.

Edema

• What it looks like: Small, blister-like bumps on the undersides of leaves.
• What causes it: Edema is caused by inconsistent watering and cool, overcast conditions, which can happen during our variable Plains spring. The plant takes up more water than it can transpire, causing cells to rupture.
• How to fix/prevent it: Improve drainage and air circulation. Avoid overwatering, especially during cool periods.

Great Plains Specific Challenges: The extreme temperature swings and variable rainfall in the Great Plains can stress geraniums, making them more susceptible to problems. Consistent watering, good drainage, and protection from strong winds are essential for success.

Geraniums make great companions for several plants in the Great Plains garden:

• Tomatoes and Peppers: Geraniums are said to repel certain pests, like tomato hornworms, that can damage these vegetables.
• Corn: The strong scent of geraniums can deter corn earworms.
• Roses: Geraniums can help protect roses from Japanese beetles.

Avoid planting geraniums near plants that prefer consistently moist soil, as geraniums prefer to dry out slightly between waterings.