Geranium in Zone 8B — Pacific Northwest

Geraniums are a delightful addition to any Pacific Northwest garden, bringing vibrant color and classic charm. Their versatility shines in containers, borders, and even hanging baskets, offering a long season of blooms that our mild summers and cool nights encourage.

While our wet springs and the occasional overcast day can present challenges, starting geraniums at the right time and providing proper care ensures a rewarding experience. With our extended 210-day growing season, you can enjoy these beauties from summer well into fall.

Starting geranium seeds indoors is possible, but honestly, most PNW gardeners find it easier to buy starts from a local nursery. If you're set on starting from seed, begin in mid-January through early February, roughly 12 weeks before you plan to transplant outdoors.

Use seed trays with a good seed-starting mix and provide warmth (around 70-75°F) and plenty of light – a grow light is especially helpful given our overcast spring days. Bottom watering prevents damping-off, a common issue with seedlings. Be patient; geraniums are notoriously slow from seed.

Transplant your geraniums outdoors in mid-April through mid-May, after the risk 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; those late spring cold snaps can still happen. For easiest results, look for healthy starts at your local nursery and transplant them into your garden.

Geraniums prefer moderate watering, so let the soil dry out slightly between waterings. Stick your finger about 2 inches deep into the soil – if it feels dry, it's time to water. Overwatering is a common problem and can lead to stem rot, so err on the side of caution.

During our dry summer months, you'll likely need to water once or twice a week, providing about an inch of water each time. Water at the base of the plant to avoid wetting the foliage, as this can encourage fungal diseases in our sometimes humid conditions. In the spring, rainfall may be enough.

Signs of underwatering include wilting leaves, while yellowing leaves can indicate overwatering. Mulching around your geraniums with compost helps retain moisture and suppress weeds, which is especially helpful during our drier periods.

Regular deadheading is key to keeping your geraniums blooming throughout the season. Simply pinch off the spent flower clusters where they meet the stem.

Throughout the summer, pinch back any leggy stems to encourage a bushier, more compact growth habit. As the first frost approaches in early November, you can bring your geraniums indoors to overwinter or simply compost them.

Geraniums are primarily grown for their beautiful blooms, which you can enjoy from late June through mid-August and beyond. There's no real "harvest" in the traditional sense.

The best way to "harvest" is to regularly remove faded blooms. This encourages the plant to keep producing new flowers.

As the weather cools in the fall, you can cut back the plants to tidy them up. If you're bringing them indoors for the winter, give them a good trim before moving them inside.

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

Botrytis Blight

• What it looks like: Grayish-brown mold on leaves, stems, and flowers, often starting with water-soaked spots.
• What causes it: High humidity and poor air circulation, which can occur during our wet springs or prolonged periods of overcast weather.
• How to fix/prevent it: Improve air circulation by spacing plants properly and pruning away crowded growth. Remove and destroy infected plant parts. Apply a fungicide if necessary.

Geranium Budworm

• What it looks like: Holes in buds and flowers, often accompanied by small, green caterpillars.
• What causes it: These caterpillars feed on geranium buds and flowers, causing damage.
• How to fix/prevent it: Handpick caterpillars when you see them. Use Bacillus thuringiensis (Bt) as a targeted treatment if infestation is heavy.

Edema

• What it looks like: Small, blister-like bumps on the undersides of leaves, which can turn brown and corky.
• What causes it: Overwatering and poor air circulation, leading to the plant taking up more water than it can transpire.
• How to fix/prevent it: Improve drainage, ensure good air circulation, and water only when the top inch of soil is dry.

Pacific Northwest Specific Challenges: Our mild heat and dry-summer humidity can be ideal for geraniums, but our wet springs can increase the risk of fungal diseases like botrytis blight. Good air circulation and proper watering are crucial for success.

Geraniums make excellent companions for several plants in the Pacific Northwest garden. They pair well with tomatoes and peppers, as their scent can deter certain pests that bother these warm-season crops, which often need a little help in our climate.

They also complement corn, helping to attract beneficial insects that prey on corn pests. Roses benefit from geraniums planted nearby, as they can help deter Japanese beetles. Avoid planting geraniums near fennel, as it can inhibit their growth.