Geranium in Zone 7A — Pacific Northwest

Geraniums are rewarding to grow in the PNW, offering vibrant color and a classic cottage garden feel. Their versatility shines in containers, borders, and even hanging baskets, and the cool nights here seem to intensify their fragrance.

While we don't have the long, scorching summers that geraniums might appreciate elsewhere, our 183-day growing season is ample time to enjoy them, especially if you get a head start. The key is proper timing, and understanding how our mild summers and wet springs affect these beauties.

Starting geraniums from seed indoors is possible, but honestly, it's a bit slow-going. If you're up for a challenge, begin in early to late February, about 12 weeks before you plan to transplant. You'll need seed trays, a heat mat to keep the soil around 70-75°F, and grow lights to provide consistent light.

Bottom watering is a must to prevent damping-off; simply set the seed trays in a shallow pan of water and let the soil absorb it from the bottom. Given our overcast spring days, those grow lights are critical for strong seedling development. Many gardeners in the PNW simply buy starts from a local nursery for easier, faster results.

Transplant your geraniums outdoors from early May through early June, after the last threat of frost has passed. Before planting, harden them off by gradually exposing them to outdoor conditions for about a week. Start with an hour or two of shade, increasing the time and sun exposure each day.

Plant them 10-12 inches apart in well-draining soil. Keep an eye on the weather forecast – those late spring showers and cool snaps can set them back if they're not properly hardened off. It's best to buy starts, as they are very slow from seed.

Geraniums need moderate watering, but it's crucial to avoid overwatering, especially with our wet springs. During the spring, when rainfall is frequent, you might not need to water them at all.

In the dry summer months, check the soil moisture using 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, delivered at the base of the plant to avoid wetting the foliage and encouraging fungal diseases.

During our mild summers, geraniums can handle the heat better than many other flowers, but they still appreciate consistent moisture. Signs of underwatering include wilting leaves and dry, crispy edges. Overwatering, on the other hand, can lead to 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 beneficial during our cooler spring and fall.

Deadheading is key to keeping your geraniums blooming all season long. Simply pinch or cut off the spent flower clusters just below the flower head, where you see a new leaf or bud forming.

Throughout the season, pinch back any leggy stems to encourage bushier growth and more blooms. As the first frost approaches in mid- October, you can bring your geraniums indoors to overwinter, or simply compost them and start fresh next year.

Geraniums are grown primarily for their beautiful flowers, which you'll start to see from mid July through late August, about 70 days after transplanting. There's no real "harvest" in the traditional sense, but regularly removing faded blooms is crucial for continued flowering.

When removing spent flowers, cut or pinch the stem just above a leaf node to encourage new growth. As the end of the season approaches and the first frost threatens in mid- October, consider taking cuttings to propagate new plants for next year. This way, you can keep your favorite varieties going.

Here are some common problems you might encounter growing geraniums in the Pacific Northwest:

Botrytis Blight

• What it looks like: Gray mold on flowers, leaves, and stems.
• What causes it: High humidity and poor air circulation, common during our wet springs.
• How to fix/prevent it: Improve air circulation by spacing plants properly and pruning out dead or diseased foliage. Water at the base of the plant and avoid overhead watering. Fungicides can be used as a last resort.

Geranium Budworm

• What it looks like: Holes in buds and flowers, often accompanied by small, green caterpillars.
• What causes it: Moths lay eggs on the plants, and the larvae feed on the buds and flowers.
• How to fix/prevent it: Handpick caterpillars off the plants. Bacillus thuringiensis (Bt) is an effective organic control.

Edema

• What it looks like: Small, water-soaked blisters on the undersides of leaves.
• What causes it: Overwatering and poor air circulation, leading to cells bursting. Common in cool, overcast conditions.
• How to fix/prevent it: Improve drainage and air circulation. Avoid overwatering, especially during periods of cool, cloudy weather.

Pacific Northwest Specific Challenges: Our mild heat and dry-summer humidity can actually be beneficial for geraniums, reducing the risk of fungal diseases compared to more humid regions. However, late blight, which affects tomatoes and potatoes, can sometimes spread to geraniums, so be vigilant about monitoring your plants and removing any infected foliage promptly. Slugs can also be a nuisance, especially in the spring, so use appropriate control measures like beer traps or diatomaceous earth.

Geraniums make excellent companions for several plants in the PNW garden. Planting them near tomatoes, peppers, and corn can help deter certain pests, as their scent repels insects. They also make great companions for roses, helping to protect them from Japanese beetles. Avoid planting geraniums near fennel, as it can inhibit their growth.