Feverfew in Zone 4A — Mountain West

Feverfew is a rewarding addition to any high-altitude garden. Its cheerful, daisy-like flowers bring a burst of summer color, and the plant's reputed medicinal properties make it a worthwhile herb to have on hand. Plus, the cool nights we get even in summer seem to intensify the aromatic oils, giving it an extra layer of interest.

Our short growing season, intense sun, and alkaline soil can present challenges, but Feverfew is surprisingly adaptable. Starting seeds at the right time or direct sowing after the last frost gives you plenty of time to enjoy its blooms within our 118-day window.

Starting Feverfew indoors is an option, especially if you want a head start on our short season. Begin in mid-March through early April, about eight weeks before you plan to transplant outdoors. Use seed trays with a good seed-starting mix, ensuring they have drainage.

Keep the trays in a warm location with plenty of light – a sunny windowsill or under grow lights works well. Bottom watering helps prevent damping off; set the tray in a shallow dish of water until the soil surface is moist. With our late springs, starting indoors gives you a jump on the season.

Transplant your Feverfew seedlings outdoors in mid-May through early June, once the danger of frost has passed. Before transplanting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the intense UV and cooler nights.

Choose a spot with full sun to partial shade and space the plants 12-15 inches apart. Be mindful of potential late frosts, which can still occur even in early June, and protect your young plants if necessary.

Direct sowing Feverfew is a simple and effective method, especially if you're not in a rush. Sow seeds outdoors in mid-May through late June, after the soil has warmed up a bit. Prepare the soil by loosening it and removing any weeds.

Sprinkle the seeds lightly over the surface and gently press them into the soil. Keep the soil consistently moist until the seedlings emerge. Thin the seedlings to 12-15 inches apart once they're a few inches tall. Direct sowing bypasses the need for indoor setup but means a later start.

Feverfew thrives with low watering once it's established. In our dry Mountain climate, overwatering is more of a concern than underwatering. During the peak of summer, from late June through August, water deeply but infrequently.

Use the "finger test" – if the top two inches of soil are dry, it's time to water. Aim for about an inch of water per week, delivered at the base of the plant to avoid wetting the foliage. In our low humidity, overhead watering is less risky, but watering at the base still minimizes potential issues.

Signs of underwatering include wilting or drooping leaves, while overwatering can lead to yellowing leaves and potential root rot. A layer of mulch around the base of the plant helps retain moisture and regulate soil temperature, conserving water in our dry climate.

Pruning Feverfew is straightforward and helps maintain its appearance and encourage more blooms. Deadhead spent flowers regularly throughout the growing season to promote continuous flowering. Simply snip off the faded blooms just below the flower head.

After the main flowering period, typically in late summer, cut the plant back by about one-third to rejuvenate it. Be aware that Feverfew self-seeds aggressively if you let the flowers go to seed. Before our first frost around mid- September, you can either leave the remaining foliage for winter interest or cut it back completely.

You can expect your first Feverfew harvest in late July through late September, about 70 days after planting. The plant is ready to harvest when the small, daisy-like flowers are in full bloom. These blooms are traditionally used for their medicinal properties.

To harvest, cut the stems just above a leaf node. Harvesting regularly encourages more blooms and keeps the plant producing throughout the season. Even as our first frost approaches in mid- September, you can continue harvesting as long as the plant is still producing flowers.

Feverfew is generally easy to grow, but here are a few common problems to watch out for in our Mountain gardens:

Self-seeds prolifically:

• What it looks like: Numerous tiny seedlings popping up everywhere in your garden the following spring.
• What causes it: Allowing the flowers to go to seed and disperse. Our cool nights and intense sun can still allow seeds to mature quickly.
• How to fix/prevent it: Deadhead spent flowers regularly to prevent seed formation. If you want to save seeds, collect them carefully before they scatter.

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).

Leaf miners:

• What it looks like: Winding, pale trails or blotches inside the leaves.
• What causes it: Larvae of small flies that tunnel between the leaf surfaces.
• How to fix/prevent it: Remove and destroy affected leaves. Use row covers to prevent adult flies from laying eggs on the plants. Neem oil can also help control leaf miner populations.

Mountain West Specific Challenges: Our moderate-at-altitude heat and low humidity mean that Feverfew is generally less susceptible to fungal diseases compared to other regions. However, the intense sun can stress the plants if they're not adequately watered, making them more vulnerable to pests.

Feverfew makes excellent companions for several plants in our Mountain gardens. Planting it near tomatoes can help deter pests like whiteflies and aphids, benefiting from Feverfew's strong scent. Roses also benefit from Feverfew as it repels aphids that often plague roses.

Many herbs, such as rosemary and thyme, grow well alongside Feverfew, creating a diverse and pest-resistant garden bed. There aren't any significant bad companions to avoid, but be mindful of giving Feverfew enough space, as it can self-seed and potentially compete with other plants.