Geranium in Zone 6B — Mountain West

Geraniums are a classic choice for the Mountain West gardener, bringing vibrant color and a delightful fragrance to our high-altitude gardens. Their versatility extends from containers on sunny patios to borders in flower beds. The satisfaction of watching them bloom through our short season is truly rewarding.

While our region presents challenges like intense sun, alkaline soil, and a short growing season, growing geraniums is achievable with careful timing. Our 163-day growing season requires us to plan ahead and give these beauties a head start.

Starting geraniums from seed indoors is possible, though it can be slow. If you're up for the challenge, begin in early to late February, about 12 weeks before you intend to transplant them outside. This gives them a good head start before our late spring arrives.

Use seed trays with a good quality seed-starting mix. Provide warmth, ideally around 70-75°F, and plenty of light. Consider using grow lights, as our early spring sunlight can be weak. Bottom watering is a great way to keep the soil consistently moist without overwatering.

Given our short growing season, many Mountain gardeners opt to purchase established geranium starts from local nurseries. This is often the easiest way to ensure a vibrant display of blooms throughout the summer.

Transplant your geraniums outdoors from early May through early June, after the risk of frost has passed. Be sure to harden them off for about a week before planting. Gradually expose them to outdoor conditions, starting with a few hours each day, to acclimate them to the intense sun and cooler nights.

Space your geraniums 10-12 inches apart to allow for good air circulation. Choose a location with full sun to part shade. Keep an eye on the weather forecast; unexpected late frosts can still occur in our Mountain region during this time.

Geraniums can be very slow to start from seed. For easiest results and biggest blooms, most gardeners here buy starts from the nursery.

Geraniums thrive with consistent, moderate watering in our dry Mountain climate. Let the soil dry slightly between waterings to prevent stem rot, which is a common issue. They tolerate our moderate-at-altitude summer heat better than many other flowering plants, but still need regular moisture.

During the hottest part of the summer, you may need to water every few days. Use the finger test: stick your finger about 2 inches deep into the soil. 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. Our low humidity minimizes the risk of fungal diseases. Signs of underwatering include wilting leaves and dry, crispy edges. Overwatering can lead to yellowing leaves and mushy stems. A layer of mulch around the base of the plants helps retain moisture and regulate soil temperature.

Regular pruning keeps geraniums looking their best and encourages continuous blooming throughout our short season. Deadheading is essential for maximizing flower production.

Remove spent flower clusters as soon as they start to fade. Simply snip them off at the base of the stem. If your geraniums become leggy, pinch back the stems to encourage bushier growth. This can be done anytime during the growing season.

As the first frost approaches in early October, you can bring your geraniums indoors to overwinter, or simply allow them to succumb to the cold.

While geraniums aren't typically harvested for consumption, they provide a continuous harvest of beautiful blooms from mid-July through early September in our region. These 70-day plants are very rewarding.

Enjoy the flowers in your garden and cut them for bouquets to bring their beauty indoors. Remove faded blooms regularly to maintain a neat appearance and encourage continued flowering.

As the first frost approaches in early October, consider taking cuttings to propagate new plants for next year. Otherwise, enjoy the last blooms before the cold weather sets in.

Here are three common problems you might encounter with geraniums in the Mountain West:

Botrytis Blight

• What it looks like: Grayish-brown mold on leaves, stems, and flowers.
• What causes it: This fungal disease is promoted by cool, damp conditions. While our region is generally dry, overcrowding and poor air circulation can create pockets of humidity.
• How to fix/prevent it: Provide good air circulation by spacing plants properly. Remove and destroy infected plant parts. Avoid overhead watering.

Geranium Budworm

• What it looks like: Small holes in buds and flowers, often accompanied by frass (insect droppings).
• What causes it: These caterpillars feed on geranium buds and flowers. They can be particularly problematic during periods of warm weather.
• How to fix/prevent it: Inspect plants regularly for signs of infestation. Handpick caterpillars or use Bacillus thuringiensis (Bt), a biological insecticide.

Edema

• What it looks like: Small, water-soaked blisters on the undersides of leaves.
• What causes it: Edema is caused by an imbalance of water uptake and transpiration. It's more common during periods of cool, cloudy weather, especially when the soil is consistently moist.
• How to fix/prevent it: Improve air circulation around plants. Avoid overwatering. Ensure good drainage.

Mountain West Specific Challenges: Our moderate-at-altitude heat and low humidity generally benefit geraniums, reducing the risk of many fungal diseases. However, the intense UV radiation can sometimes scorch leaves, so providing some afternoon shade may be beneficial. Our dry climate also means consistent watering is essential.

Geraniums make excellent companions for several plants in the Mountain West garden:

• Tomatoes: Geraniums are said to repel tomato hornworms, a common pest in our region.
• Peppers: Like tomatoes, peppers benefit from the pest-repelling properties of geraniums.
• Corn: Geraniums can attract beneficial insects that prey on corn pests.
• Roses: Geraniums planted near roses may help deter Japanese beetles.

Avoid planting geraniums near cabbage, as they can inhibit its growth.