Geranium in Zone 7B — Pacific Northwest

Geraniums are a classic choice for PNW gardens, offering vibrant color and a delightful fragrance, especially after our cool nights. They're fantastic in containers, window boxes, or adding a pop to garden beds. The mild summers and long, cool fall we experience here allow you to enjoy their blooms for an extended period.

While we may not have the scorching heat some areas do, our springs can be slow to warm, and late blight is always a concern. However, with a 193-day growing season, proper timing, and a little attention, you can absolutely enjoy beautiful geraniums.

Starting geraniums from seed indoors is possible, but be aware that they can be slow to get going. If you're eager to get a head start, aim to sow seeds from late January through mid February, roughly 12 weeks before you plan to transplant them outdoors.

Use seed trays with a good seed-starting mix and provide consistent warmth (around 70-75°F) and plenty of light, especially since our spring days can be pretty overcast. Bottom watering is a great way to keep the soil consistently moist without overwatering, which can be a problem. Honestly, though, buying starts from a local nursery is often the easiest route for geraniums.

Transplant your geraniums outdoors from late April through late May, once the danger of frost has passed. Before planting, harden them off by gradually exposing them to outdoor conditions for about a week.

Space them 10-12 inches apart in a sunny spot with well-draining soil. Keep an eye on the weather forecast around transplant time; those cool, wet springs we often get can set them back, so protect them if needed. Remember, geraniums can be slow from seed, so buying starts is often the most reliable way to get a jump on the season.

Geraniums prefer moderate watering, and it's crucial not to overwater them, especially with our sometimes wet springs. During the dry summer months, you'll need to water more regularly, but always let the top inch or two of soil dry out before watering again.

Stick your finger about 2 inches deep into the soil; if it feels dry, it's time to water. A good rule of thumb is about 1 inch of water per week, but adjust based on rainfall and temperature. It's best to water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases like botrytis blight in our climate.

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 keeps the soil cooler during our mild summers.

Deadheading is key to keeping your geraniums blooming throughout the season. Simply pinch or snip off the spent flower clusters just below the flower head.

Throughout the growing season, pinch back any leggy stems to encourage bushier growth and more blooms. As the first frost approaches around late October, you can give your plants a final tidy-up, removing any remaining flowers or yellowing leaves.

While you don't "harvest" geraniums in the traditional sense, you can expect to enjoy their colorful blooms from early July through late August, or even longer with our mild fall weather. The key is to consistently remove faded blooms to encourage continuous flowering.

When deadheading, use clean snips and cut the stem just above a leaf node. This encourages new growth and more flowers. As the end of the season approaches and temperatures cool, don't worry about removing every last faded bloom; the plant will naturally slow down its production.

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

Botrytis Blight

• What it looks like: Grayish-brown fuzzy mold on leaves, stems, and flowers.
• What causes it: High humidity and cool temperatures, especially during our wet springs and sometimes damp summers.
• How to fix/prevent it: Improve air circulation by spacing plants properly and pruning out crowded growth. Water at the base of the plant to avoid wetting the foliage. Remove and destroy any affected plant parts immediately.

Geranium Budworm

• What it looks like: Small holes in buds and flowers, often with brown frass (insect droppings) nearby.
• What causes it: Larvae of moths that feed on buds and flowers.
• How to fix/prevent it: Inspect plants regularly for signs of infestation. Handpick caterpillars or use Bacillus thuringiensis (Bt), a biological insecticide, to control them.

Edema

• What it looks like: Small, blister-like bumps on the undersides of leaves.
• What causes it: Overwatering and cool, cloudy conditions, which prevent the plant from transpiring properly.
• How to fix/prevent it: Improve drainage and avoid overwatering. Provide adequate air circulation and sunlight.

Pacific Northwest Specific Challenges: Our mild heat and dry-summer humidity can make geraniums susceptible to fungal diseases if not properly managed. Good air circulation and careful watering practices are essential for healthy plants.

Geraniums make good companions for several plants in the PNW garden. Plant them near tomatoes, peppers, and corn to help deter certain pests. They are also known to be good companions for roses, potentially repelling aphids and other rose pests. Avoid planting geraniums near fennel, as it can inhibit their growth.