Geranium in Zone 6B — Northeast

Geraniums are worth making space for in your Northeast garden because they offer a long season of vibrant color and fragrance. Their cheerful blooms brighten up containers, borders, and window boxes, and their scent is a classic summer aroma we all enjoy. Plus, they're surprisingly low-maintenance once established, making them perfect for busy gardeners looking to make the most of summer.

Our short growing season and occasional late spring frosts might seem daunting, but with a little planning, you can easily enjoy geraniums from early summer until frost. By starting seeds indoors or purchasing transplants, you'll be well on your way to success within our 183-day growing season.

Starting geraniums from seed indoors in the Northeast is possible, but honestly, it takes patience. Given our late springs, you'll need to start very early, from late January through mid February, about 12 weeks before you can think about planting them outside. If you're up for the challenge, it can be rewarding.

Use seed trays with a good seed-starting mix and provide consistent warmth (around 70-75°F) and bright light. Bottom watering helps prevent damping-off, a common issue with seedlings. Remember that spring in the Northeast often has unexpected temperature swings, so keep a close eye on your seedlings and be prepared to adjust their environment as needed.

The easiest way to grow geraniums in the Northeast is to purchase established transplants from your local garden center. However, if you've started your own indoors, you can transplant them outdoors from late April through late May, once the danger of frost has passed.

Before planting, be sure to harden off your seedlings by gradually exposing them to outdoor conditions for about a week. Plant them 10-12 inches apart in well-draining soil. Even in late April, we can still get a cold snap, so keep an eye on the forecast and be prepared to cover your young plants if necessary.

Watering geraniums correctly is key to their success in our Northeast climate. While they're relatively drought-tolerant once established, consistent moisture is important, especially during our moderate-to-humid summers. The goal is to let the soil dry slightly between waterings.

During the active growing season (late spring through summer), aim to water about once a week, providing about an inch of water. Use the "finger test" – stick your finger about two inches into the soil. If it feels dry, it's time to water. In the Northeast, we have moderate-to-humid conditions, so it's best to water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases.

Signs of underwatering include wilting leaves and dry, brittle stems. Overwatering, on the other hand, can lead to stem rot, indicated by yellowing leaves and a mushy stem base. A layer of mulch around the base of your plants helps retain moisture and suppress weeds, which is particularly helpful during our sometimes-humid summers.

Pruning geraniums is simple and essential for keeping them blooming all season long in the Northeast. The main task is deadheading: removing spent flower clusters.

Throughout the summer, regularly snip off any faded or browning flower heads just below the point where they join the stem. This encourages the plant to produce new blooms instead of putting energy into seed production. If your geraniums start to look leggy (long stems with few leaves), pinch back the stems to encourage bushier growth. As our first frost approaches around mid- October, stop deadheading to allow the plant to prepare for dormancy.

You won't be "harvesting" geraniums in the traditional sense, but you will be enjoying their blooms from early July through late August, about 70 days after starting from seed. The "harvest" is really the enjoyment of their vibrant flowers in your garden.

The best way to "harvest" geraniums is to simply enjoy their beauty and fragrance throughout the summer. Be sure to remove faded blooms regularly to maintain a neat appearance and encourage continuous flowering. As the first frost approaches in mid- October, you can take cuttings to propagate new plants indoors over the winter, or simply let the plant fade with the season.

Here are three common problems you might encounter with geraniums in the Northeast:

Botrytis Blight

• What it looks like: Grayish-brown fuzzy mold on leaves, stems, and flowers.
• What causes it: High humidity and poor air circulation, common in our Northeast summers.
• How to fix/prevent it: Improve air circulation by spacing plants properly. Remove and destroy infected plant parts. Avoid overhead watering. Consider a fungicide if the problem is severe.

Geranium Budworm

• What it looks like: Small holes in buds and flowers. You might also see small green caterpillars (budworms) inside the buds.
• What causes it: Budworms are larvae of moths that lay their eggs on geraniums.
• How to fix/prevent it: Handpick budworms when you see them. Use Bacillus thuringiensis (Bt), a biological insecticide, to control budworms.

Edema

• What it looks like: Small, blister-like bumps on the undersides of leaves.
• What causes it: Overwatering and cool, humid conditions.
• How to fix/prevent it: Improve drainage. Avoid overwatering. Ensure adequate air circulation.

Northeast Specific Challenges: The moderate heat, moderate-to-humid humidity, and even rainfall in the Northeast can create favorable conditions for botrytis blight and edema. Proper watering practices and good air circulation are essential for preventing these problems. Also, deer are always a threat, so consider deer-resistant sprays.

Geraniums make excellent companions for several plants in the Northeast garden. Plant them near tomatoes, peppers, and corn to help deter pests like aphids and certain beetles. They also look beautiful planted near roses, as they help repel Japanese beetles and other rose pests. Avoid planting geraniums near fennel, as it can inhibit their growth.