Geranium in Zone 7A — Mountain West

Geraniums are a classic for a reason, and they're right at home in our Mountain West gardens. Their vibrant colors brighten up any space, plus they're relatively low-maintenance once established. The cool nights we get here, even in summer, actually intensify their fragrance, making them even more enjoyable.

Growing geraniums in our high-altitude, short-season environment does present some challenges. But with careful timing and attention to their needs, you can enjoy beautiful blooms all summer long. Our 173-day growing season is just enough to get a good show from these beauties.

Starting geraniums from seed indoors is an option, but be warned: they are slow growers. If you're up for a bit of a challenge, starting seeds indoors from early to late February gives them a good head start. This is about 12 weeks before you can safely transplant them outside.

Use seed trays with a good seed-starting mix, providing warmth and plenty of light. Bottom watering is key to prevent damping off. Given our late springs, this indoor start helps overcome our short season at high altitude.

The easiest way to grow Geranium in the Mountain West is to buy starts. But if you've started your own indoors, or purchased seedlings, you're ready to transplant outdoors from early May through early June. Before planting, harden them off by gradually exposing them to outdoor conditions for about a week.

Plant them 10-12 inches apart in a sunny or partly shaded spot. Keep an eye on the weather, as we can still get some late frosts in May. Be ready to cover your young plants if a cold snap threatens.

Geraniums need moderate watering and are not particularly drought-tolerant, which can be tricky in our dry Mountain climate. Let the soil dry out slightly between waterings to avoid stem rot, a common issue with overwatering. Despite not being drought-tolerant, they handle our moderate summer heat better than many other flowers.

During the hottest part of the summer, you'll likely need to water deeply about once a week, providing roughly an inch of water. Use the finger test: stick your finger about two inches into the soil. If it feels dry, it's time to water. Water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases in our low-humidity environment. Mulching around the plants will also help retain moisture and keep the soil cool.

Deadheading is essential for keeping your geraniums blooming throughout the season. Simply pinch or snip off the spent flower clusters just below the flower head. This encourages the plant to produce more blooms rather than putting energy into seed production.

Throughout the summer, you can also pinch back any leggy stems to encourage bushier growth. As the first frost approaches in early October, you can bring your geraniums indoors or take cuttings to overwinter.

Geraniums are grown for their beautiful blooms, so harvesting them is really about maintaining the plant and enjoying their beauty. You can expect your first blooms from mid July through late August, depending on when you transplanted them.

Regularly remove faded blooms to keep the plants looking tidy and to encourage continued flowering. Simply snip off the dead flower heads with clean scissors or pruning shears. There's no real "end" to the harvest – just keep deadheading until the first frost hits in early October.

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

Botrytis Blight

• What it looks like: Grayish-brown fuzzy mold on leaves, stems, and flowers.
• What causes it: Fungal disease favored by cool, damp conditions. While our humidity is low, overwatering or poor air circulation can create pockets of moisture.
• How to fix/prevent it: Remove infected plant parts immediately. Improve air circulation by spacing plants properly. Water at the base of the plant and avoid overhead watering.

Geranium Budworm

• What it looks like: Holes in buds and flowers, chewed leaves, and small green caterpillars.
• What causes it: Larvae of moths that lay their eggs on geraniums.
• How to fix/prevent it: Handpick caterpillars off the plants. Use insecticidal soap or Bacillus thuringiensis (Bt) if infestation is severe.

Edema

• What it looks like: Small, raised blisters or bumps on the undersides of leaves.
• What causes it: Physiological disorder caused by inconsistent watering and cool, humid conditions. The plant takes up water faster than it can transpire it, causing cells to rupture.
• How to fix/prevent it: Ensure consistent watering, avoiding both overwatering and underwatering. Improve air circulation around the plants.

Mountain West Specific Challenges: Our intense UV can sometimes scorch geranium leaves, especially if they're not properly hardened off. While our low humidity generally helps prevent fungal diseases, inconsistent watering can still lead to problems like edema. Also be aware that occasional summer hail can damage blooms and foliage.

Geraniums make great companions for several plants in the Mountain West garden. They are known to repel certain pests, which can benefit tomatoes, peppers, and corn. Plant them near roses to help deter Japanese beetles. Avoid planting them near fennel, as it can inhibit their growth.