Geranium in Zone 6B — Midwest

Geraniums are a Midwest garden staple, adding vibrant color and classic charm to our patios and flowerbeds. They're easy to grow, even during our summer heat spells, and their cheerful blooms last for weeks, providing a beautiful contrast to our green lawns and vegetable gardens. Plus, their fragrance can help deter some pests from your tomatoes and peppers!

Sure, Midwest weather can be unpredictable, especially in spring. But by starting geraniums indoors or buying transplants, and paying attention to our typical rainfall, you can enjoy their beauty throughout our 183-day growing season.

Starting geraniums from seed indoors is possible, but honestly, they're pretty slow to get going. If you’re up for a challenge, you can start seeds indoors from late January through mid February, giving them about 12 weeks to grow before transplanting.

Use seed trays with a good seed-starting mix and provide consistent warmth and bright light, especially since our spring is moderate-to-late. Bottom watering can help prevent damping-off. Really, though, unless you're looking for a specific variety, you might find it easier to buy established plants from a local garden center.

Transplanting geraniums outdoors happens from late April through late May. Before you plant, be sure to harden them off for about a week by gradually exposing them to outdoor conditions. This helps them adjust to the Midwest's variable spring weather.

Plant them 10-12 inches apart in well-draining soil. Keep an eye on the forecast; a late frost can still happen, so be ready to cover them if needed. Because they are slow from seed, buying starts is the easiest way to get quick results.

Geraniums like moderate watering here in the Midwest, but it’s crucial not to overdo it, especially with our moderate-to-humid summers. Let the soil dry out slightly between waterings to avoid stem rot. They can tolerate the summer heat spells better than many other flowers, but still need consistent moisture.

During the spring and fall, when temperatures are cooler and rainfall is more frequent, you might only need to water once a week, if at all. In the heat of summer, when we get those 86°F days, check the soil moisture every few days. Stick your finger about 2 inches deep 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 supplemental watering. Water at the base of the plant 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 mushy stems. A layer of mulch, like shredded bark, can help retain moisture and suppress weeds, which is especially helpful with our wet-summer rainfall.

Deadheading geraniums is key to keeping them blooming all season long. Simply pinch or cut off the spent flower clusters as soon as they start to fade. This encourages the plant to put its energy into producing new blooms instead of seeds.

Throughout the growing season, you can also pinch back any leggy stems to encourage bushier growth. As the first frost approaches around mid- October, stop deadheading and let the plant prepare for dormancy. You can bring them indoors or treat them as annuals.

Geraniums aren't really harvested for eating, but you do "harvest" their beauty all season long! Expect your first blooms to appear from early July through late August, about 70 days after transplanting.

The best sign of "ripeness" is when the flower clusters are fully open and vibrant. To keep your geraniums looking their best, regularly remove faded or dead blooms. This not only improves their appearance but also encourages continuous flowering throughout the growing season.

As the first frost approaches in mid- October, it’s time to decide whether to bring your geraniums indoors for the winter or let them go. If you choose to bring them inside, cut them back and reduce watering.

Here are some common problems you might encounter with geraniums in the Midwest:

Botrytis Blight

• What it looks like: Grayish-brown mold on flowers, leaves, and stems, often starting on damaged or aging plant parts.
• What causes it: High humidity and poor air circulation, common during our wet-summer season.
• How to fix/prevent it: Improve air circulation by spacing plants adequately. Remove infected plant parts promptly. Avoid overhead watering, especially in the evening. Fungicides can be used in severe cases.

Geranium Budworm

• What it looks like: Small holes in buds and flowers, with caterpillars feeding inside. You might also see dark droppings on the foliage.
• What causes it: Moths lay eggs on the plants, and the larvae (budworms) hatch and feed on the developing buds.
• How to fix/prevent it: Inspect plants regularly for budworms. Handpick and destroy any caterpillars you find. Insecticides containing Bacillus thuringiensis (Bt) can be effective, especially when applied early in the infestation.

Edema

• What it looks like: Small, blister-like bumps on the undersides of leaves. These bumps can turn brown and corky over time.
• What causes it: Excessive moisture in the soil combined with cool temperatures and high humidity. This is most common during our variable spring weather.
• How to fix/prevent it: Improve drainage by ensuring your pots have drainage holes and your soil is well-draining. Avoid overwatering, and provide good air circulation around the plants.

Midwest Specific Challenges: Our moderate-to-hot heat and moderate-to-humid humidity can create ideal conditions for fungal diseases like botrytis blight. Be vigilant about watering practices and air circulation to keep your geraniums healthy. Additionally, our clay soil can be slow to drain, so amend it with compost or other organic matter to improve drainage.

Geraniums make great companions for several plants in a Midwest garden. They are known to help repel certain pests that bother tomatoes and peppers, making them excellent additions to your vegetable garden. Corn also benefits from geraniums, which help deter corn earworms.

Roses also benefit from having geraniums nearby, as they can deter Japanese beetles. Avoid planting geraniums near fennel, as it can inhibit their growth.