Chrysanthemum in Zone 7A — Mid-Atlantic

Chrysanthemums, or mums, are a fantastic addition to any Mid-Atlantic garden. Their late-season blooms provide a burst of color when many other flowers are fading, plus they're great for cutting and bringing indoors. The satisfaction of extending your garden's beauty well into the fall months is hard to beat.

Our humid summers and variable spring weather can present some challenges, but with proper timing and care, you can absolutely succeed with mums. Our 208-day growing season gives you plenty of time to get them established and enjoy their vibrant display.

Starting Chrysanthemum from seed indoors is an option, but honestly, most of us here in the Mid-Atlantic find it easier to buy established plants. If you're determined to start from seed, begin in early to late February, about eight weeks before you plan to transplant outdoors.

Use seed trays with a good seed-starting mix, and provide warmth and plenty of light. Bottom watering helps prevent damping-off – set the tray in a shallow dish of water until the surface of the soil is moist. Our moderate spring temperatures mean you'll need to provide consistent warmth indoors for best germination.

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

Space plants 12-18 inches apart in a sunny location. Keep an eye on the weather forecast; we sometimes get unexpected cold snaps in April. Alternatively, you can buy potted mums in the fall for instant color or purchase starts in the spring.

Chrysanthemums need consistent moisture, but overwatering in our humid Mid-Atlantic climate can lead to problems. Aim to water deeply about once a week, providing around one inch of water, unless we've had significant rainfall.

Use the "finger test" – stick your finger about two inches into the soil. If it feels dry, it's time to water. Always water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases in our humid air.

During the hottest part of the summer, you might need to water more frequently. Signs of underwatering include wilting leaves and dry soil. Overwatering can cause yellowing leaves and potentially root rot.

Applying a layer of mulch around your mums can help retain moisture and suppress weeds. Just be sure to leave some space around the stem to prevent rot, especially with our even rainfall.

Pinching your Chrysanthemum plants is key to getting a bushier shape and more blooms. Start pinching the growing tips every 2-3 weeks, removing the top inch or so of new growth.

Stop pinching around July 4th; this allows the plants to set buds for their fall bloom. Don't prune off flower buds after this date.

As the first frost approaches in late October, you can cut back the foliage after it has been killed by frost. Some gardeners leave the foliage as winter interest, but it may harbor pests and diseases.

You can expect your first harvest of Chrysanthemum blooms from mid-June through early August, depending on the variety and when you planted. The flowers last for weeks in the garden, providing a long-lasting display.

Cut the stems for bouquets when the flowers are fully open. Use sharp, clean pruners to avoid damaging the plant. Cutting the flowers encourages the plant to produce more blooms.

To ensure continued production, deadhead spent flowers regularly throughout the blooming season. As the first frost approaches in late October, you can cut the remaining blooms to enjoy indoors before they are damaged by the cold.

Chrysanthemums can encounter a few common problems in the Mid-Atlantic. Here's how to identify and deal with them:

Aphids *What it looks like:* Clusters of tiny soft-bodied insects (green, black, or white) on stems and leaf undersides. Sticky honeydew residue. Curled or distorted new growth. *What causes it:* Rapid-reproducing sap-sucking insects. Populations explode in warm weather. Ant colonies may farm them for honeydew. *How to fix/prevent it:* Strong water spray knocks them off. Encourage ladybugs and lacewings (natural predators). Insecticidal soap for heavy infestations. Neem oil works systemically. Avoid excess nitrogen fertilizer (it attracts them).

Spider Mites *What it looks like:* Fine stippling on leaves (tiny white dots). Fine webbing on leaf undersides and between stems. Leaves turn bronze or yellow. *What causes it:* Tiny arachnids that thrive in hot, dry conditions. Populations explode in drought stress. *How to fix/prevent it:* Strong water spray (daily for a week) is the best treatment. Increase humidity around plants. Neem oil or insecticidal soap. Release predatory mites (Phytoseiulus persimilis). Avoid broad-spectrum pesticides that kill predators.

Leaf Miners *What it looks like:* Tan or white squiggly lines on leaves. *What causes it:* Larvae tunneling between leaf surfaces. *How to fix/prevent it:* Remove and destroy affected leaves. Cover plants with row covers to prevent adult flies from laying eggs. Neem oil can help.

Rust *What it looks like:* Rusty orange, yellow, or brown pustules on leaves and stems, mostly on undersides. Leaves yellow and drop prematurely. *What causes it:* Various rust fungi that spread via wind-borne spores. Favored by warm, humid conditions with moisture on leaves. *How to fix/prevent it:* Remove affected leaves. Avoid overhead watering. Improve air circulation. Apply sulfur or copper fungicide. Don't work among wet plants. Rotate crops.

Mid-Atlantic Specific Challenges: Our moderate-to-hot summers and humid conditions can create a breeding ground for pests and fungal diseases on Chrysanthemums. Be vigilant about checking your plants regularly and taking action at the first sign of trouble.

Chrysanthemums benefit from companion planting. Tomatoes and peppers make good companions because they deter some pests that might bother your mums. Lettuce planted nearby can help provide ground cover, keeping the soil cooler and moister, which is especially helpful during our humid summers. Avoid planting near plants that are prone to fungal diseases, as this can increase the risk of rust and other problems in our region.