Geranium in Zone 6A — Mountain West

Geraniums are a fantastic addition to any Mountain West garden, bringing vibrant color and a classic touch to your landscape. Their resilience and ability to bloom prolifically, even with our intense sun and cool nights, make them a rewarding choice. Plus, their scent is a delightful bonus.

While our high altitude and short growing season present unique challenges, starting geraniums at the right time allows them to flourish. With a growing season that lasts about 153 days, timing is key to enjoying their blooms from summer through fall.

Starting geraniums from seed indoors in the Mountain West is possible, but be warned: they are notoriously slow growers! If you're patient, starting indoors gives you a head start on our short season.

Begin in mid-February through early March, about 12 weeks before you plan to transplant. Use seed trays with a good seed-starting mix, providing warmth (a heat mat helps) and plenty of light – a grow light is ideal. Water from the bottom to avoid damping off.

For easiest results, purchase geranium starts from your local nursery; they'll be well-established and ready to take off. If you've started your own, transplant outdoors in mid-May through mid-June, after the risk of frost has passed.

Harden off your seedlings for about a week, gradually exposing them to the outdoor elements. Plant them 10-12 inches apart in a sunny spot with well-drained soil. Keep an eye out for late frosts, which can still occur even in late spring at our elevation.

Geraniums need moderate watering, but they definitely don't like soggy feet. In our dry Mountain West climate, let the soil dry slightly between waterings to prevent stem rot. They actually tolerate heat better than many other flowers.

During the peak of summer, when temperatures reach the mid-80s, water deeply about once a week. Use the finger test: stick your finger about 2 inches into the soil; if it feels dry, it's time to water. Aim for about an inch of water per week, delivered at the base of the plant to avoid fungal issues in our low-humidity environment.

Signs of underwatering include wilting leaves and dry, crispy edges. Overwatering, on the other hand, can lead to yellowing leaves and stem rot. A light layer of mulch around the base of the plants will help retain moisture and regulate soil temperature.

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.

Throughout the summer, you can also pinch back any leggy stems to encourage a bushier, more compact growth habit. As the first frost approaches in early October, remove any remaining flowers to encourage the plant to focus its energy on root growth before winter.

Geraniums are primarily grown for their beautiful blooms, so "harvesting" is more about enjoying their visual appeal and maintaining their health. Expect your first blooms in late July through mid-September, about 70 days after transplanting.

Deadhead spent flowers regularly to encourage continuous blooming throughout the season. When harvesting flowers for bouquets, cut the stems at an angle, just above a leaf node.

As the first frost approaches in early October, remove any remaining flowers. While geraniums aren't frost-hardy, this helps the plant conserve energy.

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, often starting on damaged or fading tissue.
• What causes it: Fungal disease favored by cool, humid conditions. While our humidity is generally low, periods of prolonged rain or overhead watering can create favorable conditions.
• How to fix/prevent it: Improve air circulation by spacing plants adequately. Avoid overhead watering, and remove any infected plant parts promptly. Fungicides can be used in severe cases.

Geranium Budworm

• What it looks like: Small holes in buds and flowers, often with frass (insect droppings) nearby. You might also see caterpillars feeding on the plant.
• What causes it: Caterpillars that feed on geranium buds and flowers.
• How to fix/prevent it: Handpick caterpillars when you see them. Bacillus thuringiensis (Bt) is an effective organic insecticide that targets caterpillars.

Edema

• What it looks like: Small, blister-like bumps on the undersides of leaves, which can turn brown or corky over time.
• What causes it: Physiological disorder caused by inconsistent watering and cool temperatures, leading to cells bursting due to excess water uptake.
• How to fix/prevent it: Ensure consistent watering, avoiding both overwatering and underwatering. Improve air circulation around the plants.

Mountain West Specific Challenges: Our moderate-at-altitude heat, low humidity, and dry rainfall generally benefit geraniums, reducing the risk of fungal diseases. However, our intense sun can scorch leaves if plants aren't properly acclimated. Consistent watering is crucial to prevent edema, especially during temperature swings.

Geraniums make great companions for a variety of plants in your Mountain West garden. They are often planted near tomatoes and peppers, as their scent is believed to deter certain pests. They also pair well with corn, attracting beneficial insects that can help with pollination.

Roses also benefit from geraniums planted nearby, as they can help protect against certain fungal diseases. Avoid planting geraniums near fennel, as it can inhibit their growth.