Geranium in Zone 7A — Desert Southwest

Growing Geraniums in our Desert Southwest gardens is a rewarding experience. Their vibrant colors add beauty to our landscapes, plus they're incredibly versatile in containers or garden beds. The satisfaction of seeing these blooms thrive, even with our intense sun, makes them a worthwhile addition to any local garden.

Yes, we face challenges like extreme heat and alkaline soil, but with careful planning and attention to watering, Geraniums can flourish here. Our long 230-day growing season gives you ample time to enjoy their beauty. Timing is key, and by following a few simple guidelines, you can have Geraniums blooming in your garden.

Starting Geraniums from seed indoors is possible, but be warned: they are slow growers! It makes sense if you're after a specific variety that's hard to find as a transplant. If you want to give it a shot, start your seeds indoors in early to late January, about 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 – a grow light is really helpful. Water from the bottom to avoid damping off and ensure even moisture. Remember, our springs can bring unexpected temperature swings, so be ready to protect your seedlings if needed.

The best time to transplant your Geraniums outdoors is in early April through early May. Before transplanting, make sure to 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.

Space your Geraniums about 10-12 inches apart in well-draining soil. Honestly, for most of us, buying starts from a local nursery is the easiest way to get Geraniums going. They're very slow from seed, and this gives you a head start on the growing season.

Watering is crucial for Geraniums, especially with our extreme summer heat and arid climate. While they need moderate watering, they are NOT drought-tolerant and will suffer if left dry for too long. Overwatering, on the other hand, can lead to stem rot, so it's a delicate balance.

During the cooler spring and fall months, aim to water deeply once or twice a week, allowing the soil to dry slightly between waterings. In the extreme heat of summer, you'll likely need to water every other day, or even daily, depending on your soil and sun exposure. 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, adjusting as needed based on rainfall (especially during our monsoon season). Water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases in our arid environment.

Signs of underwatering include wilting leaves and dry, crispy edges. Overwatering can manifest as yellowing leaves and a mushy stem base. A layer of mulch around your Geraniums can help retain moisture in the soil and regulate soil temperature, which is especially helpful during the summer heat.

Regular pruning keeps your Geraniums looking their best and encourages more blooms. The key is to deadhead spent flower clusters as soon as they start to fade. This directs the plant's energy into producing new flowers rather than setting seed.

Throughout the growing season, pinch back any leggy stems to encourage bushier growth and a more compact shape. As the first frost approaches in early November, you can give your Geraniums a final trim to tidy them up, but don't prune them too severely at this time.

While you don't "harvest" Geraniums in the traditional sense, you will be enjoying their beautiful blooms from mid-June through early August. The colorful flowers are the reward for your gardening efforts. As the flowers fade, remove them to keep the plants looking tidy and to encourage continuous blooming.

Simply snip off the spent flower clusters just above a leaf node. This encourages new growth and more flowers. As the end of the season approaches, don't worry about harvesting every last bloom. Let the plants enjoy the cooler temperatures before the first frost.

Geraniums, like any plant, can face a few problems in our Desert Southwest gardens. Here are three common issues to watch out for:

Botrytis Blight

• What it looks like: Grayish-brown mold on flowers, leaves, and stems.
• What causes it: High humidity and poor air circulation, which can occur during our monsoon season.
• How to fix/prevent it: Improve air circulation by spacing plants properly and pruning out crowded growth. Avoid overhead watering, especially in the evening. Remove and destroy any infected plant parts promptly.

Geranium Budworm

• What it looks like: Holes in buds and flowers, often accompanied by small, green caterpillars.
• What causes it: Moths laying eggs on the plants, and the caterpillars then feed on the developing buds and flowers.
• How to fix/prevent it: Inspect plants regularly for caterpillars and remove them by hand. Use Bacillus thuringiensis (Bt), a biological insecticide, to control the caterpillars.

Edema

• What it looks like: Small, water-soaked blisters or bumps on the undersides of leaves.
• What causes it: Overwatering or poor drainage, combined with cool temperatures and high humidity.
• How to fix/prevent it: Improve drainage by planting in well-draining soil. Water less frequently, allowing the soil to dry 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 can also cause problems like edema if watering isn't managed carefully. During the monsoon season, be extra vigilant about botrytis blight and adjust your watering accordingly.

Geraniums can make excellent companions for certain plants in your Desert Southwest garden. They do particularly well with tomatoes and peppers, as their scent is believed to deter certain pests that commonly attack these vegetables. Corn also benefits from being near Geraniums, as they attract beneficial insects that can help control pests.

Roses are another good companion for Geraniums, as they help to repel Japanese beetles. Avoid planting Geraniums near fennel, as fennel can inhibit their growth.