Geranium in Zone 4A — Great Plains

Geraniums bring vibrant color to our Great Plains gardens, offering a cheerful display that lasts from summer's heat until frost threatens. Their classic beauty makes them perfect for containers, borders, and even adding a pop to vegetable gardens.

While our region throws its share of extreme weather at us, timing your Geranium planting just right makes it manageable. With our 138-day growing season, starting seeds indoors or buying transplants ensures you'll have plenty of time to enjoy their blooms.

Starting Geraniums from seed indoors is an option, but be warned: they can be slow to get going. If you're up for the challenge, sow seeds late February through mid March, about 12 weeks before you plan to transplant.

Use seed trays with a good seed-starting mix, and provide warmth and light. Bottom watering helps prevent damping off, which can be a problem with seedlings. Keep in mind that spring in the Plains often brings temperature swings, so monitor your seedlings closely and adjust conditions as needed.

For the easiest results in our short season, many Plains gardeners opt to buy Geranium starts from a local nursery. Whether you start your own or buy transplants, wait until late May through late June to move them outdoors.

Harden off your plants for about a week by gradually exposing them to outdoor conditions. Plant them 10-12 inches apart in a sunny spot with well-drained soil. Keep an eye on the weather forecast – late frosts and even hail can still occur at this time of year.

Geraniums need moderate watering, but they definitely don't like soggy feet. Let the soil dry slightly between waterings, and avoid overwatering, which can lead to stem rot. Luckily, they handle our summer heat better than many other flowers.

During the heat of summer, check the soil moisture regularly. Stick your finger about 2 inches deep – if it feels dry, it's time to water. Aim for about 1 inch of water per week, either from rainfall or irrigation. Water at the base of the plants to avoid wetting the foliage, which can encourage disease in our low-to-moderate humidity.

Signs of underwatering include wilting and dry, crispy leaves. Overwatering can cause yellowing leaves and stem rot. A layer of mulch around the base of the plants helps retain moisture and regulate soil temperature, which is especially helpful during our extreme temperature swings.

Regular pruning helps keep your Geraniums blooming all season long. The key is deadheading – removing spent flower clusters as soon as they start to fade.

Simply snip off the faded blooms just above a leaf node. You can also pinch back leggy stems to encourage bushier growth. As the first frost approaches in late September, stop deadheading to allow the plants to set seed, though many of us just pull them out as annuals here.

Geraniums aren't really harvested for food, but you can still enjoy their beauty throughout the growing season, from early August through mid September.

The "harvest" is simply enjoying the flowers in your garden. Remove faded blooms regularly to keep the plants looking neat and to encourage continued flowering. As the first frost approaches in late September, you can bring your Geraniums indoors to overwinter them, though many gardeners find it easier to just start fresh each year.

Geraniums can face a few problems in the Great Plains, including botrytis blight, geranium budworm, and edema.

Botrytis Blight

• What it looks like: Grayish-brown mold on leaves, stems, and flowers.
• What causes it: Humid conditions and poor air circulation. While our humidity is generally low, periods of heavy rain can create favorable conditions.
• How to fix/prevent it: Remove infected plant parts promptly. Improve air circulation by spacing plants properly and avoiding overhead watering.

Geranium Budworm

• What it looks like: Small holes in buds and flowers, often accompanied by brown frass (insect droppings).
• What causes it: Larvae of moths that feed on the buds and flowers.
• How to fix/prevent it: Handpick the caterpillars when you see them. Insecticidal soap or Bacillus thuringiensis (Bt) can also be effective.

Edema

• What it looks like: Small, water-soaked blisters on the undersides of leaves.
• What causes it: Excessive moisture in the soil combined with cool temperatures and high humidity.
• How to fix/prevent it: Improve drainage by ensuring your soil is well-draining. Avoid overwatering and provide good air circulation.

Great Plains Specific Challenges: Our extreme weather swings can make it tricky to manage these problems. The combination of hot heat, low-to-moderate humidity, and variable rainfall can stress plants, making them more susceptible to disease and pests. Consistent monitoring and prompt action are key to keeping your Geraniums healthy in the Plains.

Geraniums make good companions for several plants in the Great Plains garden. They are said to repel certain pests, benefiting:

• Tomatoes and Peppers: Geraniums may help deter tomato hornworms and pepper weevils.
• Corn: Geraniums may repel the corn earworm.
• Roses: Geraniums can help deter Japanese beetles.

Avoid planting Geraniums near: No bad companions to note.