Geranium in Zone 6A — Mid-Atlantic

Geraniums are a classic choice for Mid-Atlantic gardens, bringing vibrant color and a touch of old-fashioned charm. They thrive in our four seasons, offering continuous blooms throughout the summer months, adding beauty to beds, borders, and containers. Plus, their versatility extends beyond aesthetics – some varieties are edible, and their fragrance can deter certain pests.

While we Mid-Atlantic gardeners contend with humid summers and deer pressure, growing geraniums successfully is very achievable. By starting seeds indoors at the right time and timing your transplant, you’ll be set up for success. Our roughly 188-day growing season gives you plenty of time to enjoy these beauties.

Starting geraniums from seed indoors is possible, but be warned: they're notoriously slow growers. It's often easier to buy established starts from a local garden center. However, if you’re feeling ambitious, you can sow seeds indoors from late January through mid February, giving them about 12 weeks to get a head start before transplanting.

Use seed trays filled with a good quality seed-starting mix. Keep the soil consistently moist (bottom watering helps prevent damping off) and provide warmth – a heat mat can be very helpful. Once seedlings emerge, ensure they receive plenty of light, either from a sunny windowsill or a grow light. Given our moderate spring character here in the Mid-Atlantic, indoor growing offers protection from our variable weather.

Transplant your geraniums outdoors from late April through late May, once the danger of late frost has passed. Before planting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week. This acclimates them to the sun and wind, preventing transplant shock.

Choose a location with full sun to part shade and space plants 10-12 inches apart. Be prepared for some unpredictable weather during this time. Although the date of last frost is mid-April, sometimes we get a surprise. Buying starts means you can wait until the weather is stable.

Geraniums in the Mid-Atlantic appreciate moderate watering. Let the soil dry slightly between waterings to avoid problems with stem rot, which is common in our humid summers. While they don't like being waterlogged, they also aren't very drought tolerant.

During the hotter months of July and August, you might need to water a couple of times a week, especially if it hasn't rained recently. Use the "finger test" – stick your finger about 2 inches into the soil. If it 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 climate.

Signs of underwatering include wilting leaves and dry, crispy edges. Overwatering, on the other hand, can lead to yellowing leaves and soft, mushy stems. A layer of mulch, like shredded hardwood, can help retain moisture in the soil and suppress weeds.

Deadheading is key to keeping your geraniums blooming throughout the season. Snip off spent flower clusters as soon as they start to fade. This encourages the plant to produce new blooms instead of putting energy into seed production.

Throughout the growing season, you can also pinch back any leggy stems to encourage bushier growth. This involves snipping off the tips of the stems just above a leaf node. As the first frost approaches around mid- October, stop deadheading to allow the plant to focus on hardening off for winter, if you plan to overwinter it indoors.

While most people grow geraniums for their beauty, some varieties have edible flowers and leaves. Expect your first blooms to appear from early July through late August, about 70 days after transplanting.

Harvest the flowers or leaves in the morning, after the dew has dried. Use sharp scissors or pruners to cut the stems, being careful not to damage the plant. Even if you don't plan to eat them, remove faded blooms regularly to keep the plants looking neat and encourage continued flowering.

As the weather cools in late summer, geraniums will naturally slow down their production. If you want to keep your geraniums blooming longer, consider bringing them indoors before the first frost.

Here are a few common problems to watch out for with geraniums in the Mid-Atlantic:

Botrytis Blight

• What it looks like: Gray, fuzzy mold on leaves, stems, and flowers, often starting with brown spots.
• What causes it: High humidity and poor air circulation create ideal conditions for this fungal disease. Our humid Mid-Atlantic summers make it particularly problematic.
• How to fix/prevent it: Improve air circulation by spacing plants adequately. Remove and destroy infected plant parts promptly. Apply a fungicide if necessary. Water at the base of the plants to avoid wetting the foliage.

Geranium Budworm

• What it looks like: Small holes in buds and flowers, with caterpillars inside.
• What causes it: These pests are attracted to geraniums and can quickly decimate the blooms.
• How to fix/prevent it: Inspect plants regularly for caterpillars. Handpick and remove them. Use Bacillus thuringiensis (Bt) as a biological control if infestation is heavy.

Edema

• What it looks like: Small, blister-like bumps on the undersides of leaves, which can turn brown and corky.
• What causes it: Inconsistent watering and high humidity can cause edema. The plant takes up water faster than it can be transpired, leading to cell damage.
• How to fix/prevent it: Ensure consistent watering and good drainage. Improve air circulation around the plants. Avoid overwatering.

Mid-Atlantic Specific Challenges: Our moderate-to-hot summers, high humidity, and even rainfall can create favorable conditions for fungal diseases and pests. Regular monitoring and preventative measures are key to keeping your geraniums healthy and thriving in the Mid-Atlantic.

Geraniums make good companions for several plants in the Mid-Atlantic garden. Plant them near tomatoes, peppers, and corn. Geraniums may help deter certain pests, protecting these crops. They also pair well with roses, as they can help repel Japanese beetles, which are a major nuisance in our region. Avoid planting geraniums near fennel, as it can inhibit their growth.