Geranium in Zone 5B — Mountain West

Geraniums are a classic for a reason, and they bring a lot to the table in our Mountain West gardens. Their bright blooms add cheer to containers and borders, and their fragrance is a welcome bonus. Plus, they're relatively easy to grow, offering a big reward for a reasonable amount of effort.

Our high-altitude climate presents some unique challenges, like intense sun and a short growing season. But with careful timing and a few tricks, you can absolutely enjoy beautiful geraniums. We're dealing with about 149 days between frosts, so let's make the most of them.

Starting geraniums from seed indoors gives you a head start, but honestly, it's a slow process. If you're patient and enjoy the challenge, go for it. Otherwise, buying starts from a local nursery is perfectly fine, especially given our short season.

If you decide to start indoors, aim for mid-February through early March, roughly 12 weeks before you plan to transplant. Use seed trays with a good seed-starting mix, and keep them warm (around 70-75°F) until germination. A heat mat can really help. Bottom watering is ideal to avoid damping off. Remember, our springs here in the Mountain West often start late, so don't rush things.

Transplant your geraniums outdoors from mid-May through mid-June, after the risk of frost has passed. Before planting, harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the intense sun and cooler nights we often have.

Plant them 10-12 inches apart in well-draining soil. Keep an eye on the weather; a late frost or even a hailstorm can set them back, so be ready to cover them if needed. Again, don't be afraid to buy starts. They'll get you to blooms faster.

Geraniums like consistent moisture but don't want to be soggy, which can be a tricky balance in our dry Mountain West climate. Aim to let the top inch or two of soil dry out between waterings. Stick your finger in to check – that's the best way to tell.

During the peak of summer (when we might hit 85°F), you'll probably need to water deeply a couple of times a week, giving them about an inch of water each time. Water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases, even with our low humidity. In the cooler shoulder seasons of spring and fall, you can cut back on watering.

Signs of underwatering include wilting leaves and dry soil. Overwatering can lead to yellowing leaves and potentially stem rot. A layer of mulch around the base of the plants helps retain moisture and keeps the soil cooler, which is especially helpful in our intense sun.

Deadheading is key to keeping your geraniums blooming all season long. Simply pinch or snip off the spent flower clusters just below the flower head. This encourages the plant to put its energy into producing new blooms instead of seeds.

Throughout the summer, you can also pinch back any leggy stems to encourage bushier growth. As the first frost approaches in early October, stop deadheading to allow the plant to prepare for dormancy.

You're not really "harvesting" geraniums for food, but you are harvesting their beauty. Expect your first blooms in late July through mid-September, about 70 days after transplanting. The flowers will be vibrant and full.

The best sign of "ripeness" is simply when the flowers are fully open and colorful. Regularly removing faded blooms not only keeps the plant looking tidy but also encourages continuous flowering throughout the season. As the first frost approaches, you can bring potted geraniums indoors to overwinter, or take cuttings to propagate new plants.

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

Botrytis Blight

• What it looks like: Grayish-brown mold on flowers, leaves, and stems.
• What causes it: This fungal disease thrives in cool, humid conditions. While our humidity is low, overcrowding and poor air circulation can create pockets of moisture.
• How to fix/prevent it: Provide good air circulation by spacing plants properly. Remove infected plant parts promptly. Avoid overhead watering, and consider a fungicide if the problem is severe.

Geranium Budworm

• What it looks like: Small holes in flower buds and petals. You might also find small, greenish caterpillars inside the buds.
• What causes it: These caterpillars feed on the buds and flowers, causing damage and preventing blooms.
• How to fix/prevent it: Inspect your plants regularly for signs of budworms. Handpick any caterpillars you find. Bacillus thuringiensis (Bt) is an effective organic control option.

Edema

• What it looks like: Small, raised blisters or bumps on the undersides of leaves.
• What causes it: Edema is caused by inconsistent watering and cool temperatures, which can happen during our spring temperature swings. The plant takes up more water than it can transpire, causing cells to rupture.
• How to fix/prevent it: Ensure consistent watering and good drainage. Avoid overwatering, especially during cool periods. Improve air circulation around the plants.

Mountain West Specific Challenges: Our moderate-at-altitude heat and low humidity are generally favorable for geraniums, but our intense sun can sometimes scorch the leaves, so provide some afternoon shade if needed. The dry rainfall means you'll need to be diligent about watering, but it also reduces the risk of many fungal diseases.

Geraniums make good companions for several plants in our Mountain West gardens:

• Tomatoes: Geraniums are said to repel certain pests that attack tomatoes, such as tomato hornworms.
• Peppers: Similar to tomatoes, geraniums can help deter pests that bother peppers.
• Corn: Geraniums can attract beneficial insects that prey on corn pests.
• Roses: Geraniums can help deter Japanese beetles, which can be a problem for roses.

Avoid planting geraniums near fennel, as it can inhibit their growth.