Geranium in Zone 9A — Desert Southwest

Geraniums bring a classic, vibrant charm to our Desert Southwest gardens. Their bright blooms thrive in containers or garden beds, offering a long season of color. The satisfaction of growing your own geraniums, with their lovely scent and cheerful appearance, is well worth the effort in our unique climate.

Desert gardening comes with its own set of challenges, from our extreme heat to alkaline soil. But with careful timing and a few smart strategies, you can absolutely enjoy thriving geraniums during our long, 298-day growing season. We'll focus on getting them established during our milder periods to ensure summer survival.

Starting geraniums from seed indoors is possible, but it requires patience. Geraniums are notoriously slow to get going from seed, so most gardeners in our region find it easier to purchase starts from a local nursery. If you want to try starting your own, begin in late November through late December, about 12 weeks before you plan to transplant them outdoors.

Use seed trays with a good quality seed-starting mix. Keep the soil consistently moist, watering from the bottom to avoid damping off. Provide warmth and plenty of light, using grow lights if necessary, especially since our spring character is very-early and days are short.

Transplant your geraniums outdoors in early to late March, after the danger of frost has passed. Before transplanting, harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the intense Desert Southwest sun and temperature fluctuations.

Choose a location with full sun to part shade, spacing plants 10-12 inches apart. Prepare the soil with compost to improve drainage and fertility. Be aware that we can still get some unexpected temperature dips during this time, so keep an eye on the forecast and be prepared to cover your young plants if needed.

Moderate watering is key for geraniums in our arid climate. Aim to keep the soil consistently moist but not soggy. Overwatering can lead to stem rot, a common problem in the Desert Southwest where our alkaline soil doesn't always drain well.

During the cooler spring and fall months, water thoroughly once or twice a week, providing about 1 inch of water each time. Use the finger test: stick your finger about 2 inches deep into the soil. If it feels dry, it's time to water. In the extreme heat of summer, you may need to water more frequently, possibly every other day, especially if they're in containers. Water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases in our monsoon moisture.

Signs of underwatering include wilting leaves and dry, crispy edges. Overwatering symptoms include yellowing leaves and a soft, mushy stem. A layer of mulch around the base of the plants helps retain moisture and regulate soil temperature.

Regular pruning keeps your geraniums looking their best and encourages more blooms. Deadhead spent flower clusters as soon as they start to fade. This directs the plant's energy into producing new flowers rather than seeds.

Throughout the growing season, pinch back any leggy stems to promote bushier growth. Simply snip off the tips of the stems just above a leaf node. As the first frost approaches in early December, you can give your geraniums a final trim to tidy them up before the winter months.

Geraniums are primarily grown for their ornamental value, so "harvesting" is more about maintaining their appearance and encouraging continued blooming. Expect your first flowers in early May through late June, about 70 days after transplanting.

The primary harvest task is deadheading. Remove faded blooms regularly to keep the plants looking neat and to encourage more flowers. Simply snip off the entire flower stem just above a leaf node.

As the first frost approaches in early December, you can take cuttings from your favorite geraniums to propagate new plants indoors over the winter. This allows you to enjoy their beauty year after year.

Here are three common problems you might encounter with geraniums in our Desert Southwest gardens:

Botrytis Blight

• What it looks like: Grayish-brown mold on leaves, stems, and flowers.
• What causes it: High humidity and poor air circulation. The monsoon moisture can create favorable conditions for this fungus.
• How to fix/prevent it: Improve air circulation by spacing plants properly. Remove and destroy infected plant parts immediately. Avoid overhead watering, and consider using a fungicide if the problem is severe.

Geranium Budworm

• What it looks like: Holes in flower buds and leaves. You might also see small, green caterpillars.
• What causes it: These caterpillars feed on geraniums, causing damage to the buds and foliage.
• How to fix/prevent it: Handpick caterpillars off the plants. Use Bacillus thuringiensis (Bt) as a biological control. Monitor plants regularly for signs of infestation.

Edema

• What it looks like: Small, blister-like bumps on the undersides of leaves.
• What causes it: Overwatering and poor drainage, especially during cool, cloudy weather. This is due to cells rupturing from water pressure.
• How to fix/prevent it: Improve drainage by amending the soil with compost. Water less frequently, allowing the soil to dry out slightly between waterings. Ensure good air circulation around the plants.

Desert Southwest Specific Challenges: Our extreme heat can stress geraniums, making them more susceptible to pests and diseases. The arid humidity means they need consistent watering, but our alkaline soil can lead to drainage problems if not properly amended. Monitor your plants closely and adjust your care routine to suit our unique climate.

Geraniums play well with several plants in the Desert Southwest garden. Plant them near tomatoes and peppers, as their scent is believed to deter certain pests that bother these vegetables. Corn also makes a good companion, providing some afternoon shade during our intense summer heat.

Roses benefit from geraniums planted nearby, as they are said to repel Japanese beetles. Avoid planting geraniums near fennel, as it can inhibit their growth.