Geranium in Zone 7B — Mid-Atlantic

Geraniums offer a classic, cheerful look for your Mid-Atlantic garden, providing vibrant color all season long. Their versatility shines in containers, borders, and even as bedding plants, thriving in our humid summers. Growing geraniums brings immense satisfaction, as their bright blooms add a touch of cottage charm to any landscape.

While our region's humidity and occasional deer pressure present challenges, the long 214-day growing season in Zone 7B gives you ample time to cultivate healthy and beautiful geraniums. Starting at the right time and paying attention to watering will set you up for success.

Starting geraniums from seed indoors in the Mid-Atlantic is possible, but be aware that they are very slow to mature. If you want a head start, begin your seeds indoors from mid January through early February, about 12 weeks before you plan to transplant them outdoors.

Use seed trays with a good seed-starting mix, and provide warmth (a heat mat helps) and bright light (grow lights are ideal). Bottom watering is your friend here – set the tray in a shallow dish of water to allow the soil to soak it up, preventing damping-off.

The ideal time to transplant your geraniums outdoors in the Mid-Atlantic is mid April through mid May. Remember to harden off your seedlings for about a week before transplanting. Gradually expose them to outdoor conditions, starting with a few hours of shade and increasing the time and sun exposure each day.

Space your geraniums 10-12 inches apart to allow for good air circulation, which is especially important in our humid climate. While you can start from seed, most gardeners in our region find it much easier and faster to buy established starts from a local nursery. This bypasses the slow early growth phase and gives you a jump on the season. Watch for late frost as the weather can be variable.

Geraniums need moderate watering, but overwatering is a common mistake in our humid Mid-Atlantic climate. The key is to let the soil dry out slightly between waterings to prevent stem rot. They can tolerate the summer heat better than many other flowers, but wilting is a sign they need a drink.

During the spring and fall, when temperatures are cooler and rainfall is more frequent, you might only need to water once or twice a week. In the heat of summer, you may need to water every other day, depending on rainfall. Stick your finger about two inches deep into the soil – if it feels dry, it's time to water. Aim for about an inch of water per week, including rainfall.

Water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases in our humid environment. Signs of underwatering include wilting and dry, crispy leaves, while overwatering can cause yellowing leaves and stem rot. A layer of mulch around the base of the plants helps retain moisture and suppress weeds.

Pruning geraniums is simple and essential for keeping them blooming beautifully throughout our Mid-Atlantic growing season. The main task is deadheading, which means removing spent flower clusters.

Pinch off the faded blooms just below the flower head to encourage the plant to produce more flowers. Throughout the season, you can also pinch back any leggy stems to encourage bushier growth. As the first frost approaches in early November, you can bring your geraniums indoors to overwinter as houseplants or take cuttings to propagate new plants for next year.

Geraniums aren't harvested for consumption; they're grown for their beautiful blooms. Expect your geraniums to start flowering in late June through mid August, about 70 days after starting from seed (or soon after transplanting starts).

Enjoy the flowers in your garden, and regularly remove faded blooms to keep the plants looking tidy and to encourage continuous flowering. To harvest, simply snip off the entire flower stalk with clean pruners.

As the end of the season approaches and the first frost threatens in early November, you can take cuttings from your favorite geraniums to propagate new plants indoors over the winter. This way, you'll have a head start on next year's garden.

Geraniums, like all plants, can face challenges in our Mid-Atlantic environment. Here are three common problems and how to address them:

Botrytis Blight

• What it looks like: Grayish-brown mold on flowers, leaves, and stems, often starting with water-soaked spots.
• What causes it: High humidity and poor air circulation create ideal conditions for this fungal disease.
• How to fix/prevent it: Remove and destroy infected plant parts. Improve air circulation by spacing plants properly and pruning out crowded growth. Avoid overhead watering, and consider using a fungicide if the problem is severe.

Geranium Budworm

• What it looks like: Small holes in flower buds and leaves, often accompanied by caterpillars inside the buds.
• What causes it: These caterpillars feed on buds and foliage, causing damage and preventing blooms.
• How to fix/prevent it: Handpick caterpillars when you see them. Use insecticidal soap or Bacillus thuringiensis (Bt) to control infestations. Regularly inspect plants for signs of damage.

Edema

• What it looks like: Small, blister-like bumps on the undersides of leaves, which can turn brown and corky.
• What causes it: Edema is caused by the plant taking up more water than it can transpire, often due to cool, wet conditions and poor air circulation.
• How to fix/prevent it: Improve air circulation around plants. Avoid overwatering, and ensure good drainage. Provide adequate sunlight to promote transpiration.

Mid-Atlantic Specific Challenges: The moderate-to-hot summers and humid conditions in the Mid-Atlantic can create favorable conditions for fungal diseases like botrytis blight. Consistent rainfall can also contribute to edema if drainage is poor. Regular monitoring and proactive measures are key to keeping your geraniums healthy and thriving.

Geraniums benefit from companion planting in the Mid-Atlantic garden. Plant them near tomatoes, peppers, and corn to help deter certain pests. Geraniums are said to repel tomato hornworms and other insects that can damage these crops.

Roses also make good companions, as geraniums can help protect them from Japanese beetles. Avoid planting geraniums near fennel, as it can inhibit their growth.