Geranium in Zone 7B — Northern California

Geraniums are a classic choice for NorCal gardens, bringing vibrant color and a touch of old-world charm to our patios and borders. Their versatility shines in containers, window boxes, and even as edging plants, adding beauty throughout our long growing season. Plus, their fragrance is a lovely bonus.

While we face water restrictions and occasional heat waves here in Northern California, Geraniums are surprisingly resilient when given proper care and attention. Our 245-day growing season gives you plenty of time to enjoy their blooms.

Starting Geraniums from seed indoors is an option, but be warned, they can be slow to get going. If you're itching to get a head start, sow seeds indoors from late December through mid January, giving them about 12 weeks before transplanting.

Use seed trays with a good seed-starting mix. Keep them consistently warm, ideally around 70-75°F, and provide ample light – a grow light works wonders. Bottom watering is a great way to keep the soil moist without overwatering, which can lead to damping off.

Given our early spring in Northern California, starting indoors gives you a jump, but honestly, buying established starts from a local nursery is often the easiest and fastest route to beautiful Geraniums.

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

Space them 10-12 inches apart to allow for good air circulation. Be mindful of our spring weather; a late cold snap can happen, so keep an eye on the forecast and be prepared to cover them if needed. Buying starts from a local nursery is often the easiest and fastest route to beautiful Geraniums.

Watering is crucial for Geraniums in our Mediterranean climate. While they tolerate heat better than some flowers, consistent moisture is key, especially during our dry summers. However, overwatering is a no-no, as it can lead to stem rot.

During the cooler spring months, water deeply once a week, letting the soil dry slightly between waterings. As the weather heats up in summer, you may need to increase watering to 2-3 times per week. Use 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 an inch of water per week, delivered at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases in our sometimes humid microclimates.

Signs of underwatering include wilting leaves and dry, cracked soil. Overwatering symptoms include yellowing leaves and soggy soil. A layer of mulch, like shredded bark, will help retain moisture and keep the soil cool.

Deadheading is essential for keeping your Geraniums blooming throughout our long growing season. Simply pinch off spent flower clusters just below the flower head to encourage new growth.

Throughout the season, you can also pinch back any leggy stems to promote a bushier, more compact shape. As the first frost approaches in mid- November, you can either bring your Geraniums indoors to overwinter or let them die back naturally.

Geraniums are primarily grown for their beautiful blooms, so "harvesting" is more about enjoying their beauty in the garden. Expect your first blooms to appear from early June through late July, about 70 days after starting from seed.

Continuously remove faded or dead flowers to encourage more blooms throughout the season. To "harvest" a bloom, simply snip the stem just below the flower head with clean pruners. This encourages the plant to put energy into producing more flowers.

As the weather cools in late fall and the first frost nears around mid- November, you can bring your Geraniums indoors to overwinter if you wish, or simply enjoy the last of their blooms before the season ends.

Geraniums, like all plants, can face challenges. Here are three common problems in Northern California gardens:

Botrytis Blight

• What it looks like: Gray mold on flowers, leaves, and stems.
• What causes it: High humidity and poor air circulation create ideal conditions for this fungal disease. In NorCal, this is more common in coastal microclimates with morning fog.
• How to fix/prevent it: Improve air circulation by spacing plants properly and pruning out crowded growth. Avoid overhead watering, and remove any infected plant material promptly. Fungicides can be used in severe cases.

Geranium Budworm

• What it looks like: Holes in buds and flowers, often accompanied by small, green caterpillars.
• What causes it: These caterpillars are the larvae of moths that lay their eggs on Geraniums.
• How to fix/prevent it: Handpick caterpillars when you see them. Bacillus thuringiensis (Bt) is an effective organic control option.

Edema

• What it looks like: Small, blister-like bumps on the undersides of leaves.
• What causes it: Edema is caused by inconsistent watering, especially when the soil is kept too wet.
• How to fix/prevent it: Ensure good drainage and allow the soil to dry slightly between waterings.

Northern California Specific Challenges: Our dry summers can stress Geraniums, making them more susceptible to pests and diseases. Consistent watering and good air circulation are key to keeping your plants healthy. Be mindful of water restrictions and choose water-wise gardening practices.

Geraniums make great companions for several plants in our Northern California gardens. They are said to repel certain pests, benefiting:

• Tomatoes and Peppers: Geraniums may deter tomato hornworms and other pests that plague these crops.
• Corn: Geraniums can help repel corn earworms.
• Roses: Geraniums are often planted near roses to deter Japanese beetles.

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