Geranium in Zone 7A — Southeast

Geraniums are a classic choice for Southeast gardens, offering vibrant color and a long bloom season that perfectly complements our long summer. They're versatile enough for containers, borders, or even mass plantings, bringing a cheerful touch to any landscape.

Our hot, humid summers can present challenges like fungal diseases and hungry pests. The timing of planting and proper care makes all the difference. With our 225-day growing season, you have plenty of time to enjoy these beauties if you start smart.

Starting geraniums from seed indoors is possible, but be warned: they are slow growers. If you want a jump start, you can sow seeds indoors from early to late January, giving them about 12 weeks to get a head start before transplanting.

Use seed trays with a good seed-starting mix. Keep them consistently warm and provide plenty of light – a grow light is ideal. Don't forget to water from the bottom to prevent damping off, a common problem in our humid climate. Given our moderate spring temperatures, you might find it easier to simply purchase established starter plants.

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

Space them about 10-12 inches apart to allow for good air circulation, which is crucial in our humid climate. Be mindful of late season cold snaps that can occur in early spring. Buying established plants from a local nursery is a great way to ensure success.

Watering is critical for geraniums, especially in the Southeast's hot and humid climate. While they prefer moderate moisture, overwatering can quickly lead to stem rot. It's a fine balance!

During the hotter months of June, July, and August, check the soil moisture every few days. Stick your finger about 2 inches deep; if the soil feels dry, it's time to water. Aim for about an inch of water per week, either from rainfall or irrigation. Water at the base of the plants to avoid wetting the foliage, which can encourage fungal diseases in our humid air.

In early spring and fall, when temperatures are milder and rainfall is more frequent, you'll likely need to water less often. Yellowing leaves can indicate overwatering, while wilting leaves suggest underwatering. A layer of pine straw or shredded hardwood mulch can help retain moisture and suppress weeds, but avoid piling it up against the stems.

Regular pruning, or deadheading, will keep your geraniums blooming beautifully throughout our long growing season. The key is to remove spent flower clusters as soon as they start to fade.

Simply snip off the entire flower stem just above a leaf node. If your plants start to look leggy, you can pinch back the stems to encourage bushier growth. As the first frost approaches in early November, you can give your plants a final trim to tidy them up before the cold weather arrives.

While geraniums are primarily grown for their beautiful flowers, you can still "harvest" them by deadheading spent blooms from mid-June through early August. This encourages continuous flowering, giving you a long-lasting display of color.

Look for faded or dried-up flower heads as your signal to harvest. Use clean pruning shears to remove the entire flower stem. Keep deadheading regularly throughout the growing season to keep your plants looking their best. As the first frost approaches in early November, remove any remaining blooms and prepare your plants for winter.

Geraniums, like many plants in the Southeast, can face specific challenges due to our climate. Here are three common problems and how to tackle them:

Botrytis Blight

• What it looks like: Grayish-brown fuzzy mold on flowers, leaves, and stems.
• What causes it: High humidity and poor air circulation create the perfect environment for this fungal disease.
• How to fix/prevent it: Improve air circulation by spacing plants adequately. Avoid overhead watering, and remove any infected plant parts immediately. A fungicide may be necessary in severe cases.

Geranium Budworm

• What it looks like: Holes in flower buds and leaves, often with small, green caterpillars present.
• What causes it: These caterpillars feed on geraniums, causing significant damage.
• How to fix/prevent it: Handpick caterpillars when you see them. Bacillus thuringiensis (Bt) is an effective organic treatment. Monitor your plants regularly for signs of infestation.

Edema

• What it looks like: Small, blister-like bumps on the undersides of leaves.
• What causes it: Edema is caused by inconsistent watering and overly moist soil conditions, which are common in our wet-summer climate.
• How to fix/prevent it: Ensure good drainage and avoid overwatering. Allow the soil to dry slightly between waterings.

Southeast Specific Challenges: The hot, humid summers and frequent afternoon thunderstorms in the Southeast create ideal conditions for fungal diseases. Consistent monitoring, proper watering practices, and good air circulation are essential for keeping your geraniums healthy and thriving.

Geraniums make great companions for several plants in your Southeast garden. They deter certain pests, which can benefit nearby vegetables.

Tomatoes and peppers thrive alongside geraniums because the flowers help repel tomato hornworms and pepper weevils. Corn can also benefit, as geraniums can help deter corn earworms. Roses also appreciate geraniums as neighbors, as they help repel Japanese beetles, which can be a major problem here. Avoid planting geraniums near fennel, as it can inhibit their growth.