Borage in Zone 8B — Southern California

Borage is a fantastic addition to any Southern California garden. Its vibrant blue, star-shaped flowers attract pollinators, and the cucumber-flavored leaves and edible flowers add a unique touch to salads and drinks. Plus, it's a relatively easy plant to grow, even with our mild winters and long growing season, promising a year-round harvest.

While we face challenges like drought and the occasional Santa Ana winds, borage is a resilient plant that can thrive here with proper care. Our 298-day growing season gives you plenty of time to enjoy this versatile herb.

You can transplant borage seedlings outdoors from early February through early March. Before planting, harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the sun and wind.

Space the seedlings 12-18 inches apart to allow for adequate growth. Be mindful of potential late frosts or unexpected temperature swings during this time, and provide temporary protection if needed.

Direct sowing is the preferred method for borage, and it's super easy! Sow seeds mid February through early October, when the soil has warmed up a bit. Borage germinates best when soil temperatures are consistently above 60°F.

Prepare the soil by loosening it and adding some compost. Sow seeds about 1/2 inch deep and 12-18 inches apart. Keep the soil consistently moist until germination, which usually takes about a week or two. Be aware that borage self-seeds readily, so be prepared to manage seedlings in future seasons.

Borage needs moderate watering, especially during our hot, dry summers. While it's not particularly drought-tolerant, it's also not fussy. The key is to find the right balance for our climate.

During the cooler, wetter months, from late fall through early spring, you may only need to water once a week, or even less if we're getting regular rainfall. In the heat of summer, however, you'll likely need to water every other day, providing about 1 inch of water per week. Always check the soil moisture before watering – stick your finger about 2 inches deep. If it feels dry, it's time to water.

Water at the base of the plant to avoid wetting the foliage, which can encourage powdery mildew in our low-to-moderate humidity. Signs of underwatering include wilting leaves, while yellowing leaves can indicate overwatering. Adding a layer of mulch around the base of the plant helps retain moisture and keep the soil cool.

You can expect your first borage harvest starting mid April through mid December, about 55 days after sowing. Look for the star-shaped blue flowers to be fully open – these are edible and add a lovely touch to salads or drinks. The young leaves are also edible and have a refreshing cucumber flavor.

To harvest, simply snip off the flowers or leaves as needed. Avoid taking too many leaves at once, as this can stress the plant. Regular harvesting encourages continued production. As first frost approaches in early December, you can still harvest leaves and flowers, though growth will slow down. You can also let some plants go to seed to ensure a supply for the following year.

Here are some common problems you might encounter with borage in Southern California:

Self-seeding aggressively

• What it looks like: Numerous borage seedlings popping up in unexpected places throughout your garden.
• What causes it: Borage readily drops its seeds, and our mild winters allow them to germinate easily.
• How to fix/prevent it: Deadhead flowers before they go to seed. Remove unwanted seedlings promptly. Consider growing borage in containers to limit its spread.

Powdery mildew

• What it looks like: White or grayish powdery coating on leaves, stems, and sometimes fruit. Leaves curl, yellow, and die.
• What causes it: Various fungi that thrive in warm days, cool nights, and moderate humidity. Dry leaf surfaces actually favor it.
• How to fix/prevent it: Improve air circulation through spacing and pruning. Remove affected leaves. Neem oil or potassium bicarbonate sprays help. Milk spray (1 part milk to 9 parts water) is surprisingly effective.

Can become leggy

• What it looks like: Long, bare stems with leaves concentrated at the tips.
• What causes it: Insufficient sunlight or overcrowding can cause borage to stretch towards the light, resulting in a leggy appearance.
• How to fix/prevent it: Ensure your borage plants receive at least 6 hours of sunlight per day. Space plants adequately to allow for good air circulation and light penetration. Prune back leggy stems to encourage bushier growth.

Southern California Specific Challenges: Our hot summers can stress borage, increasing its susceptibility to powdery mildew. Santa Ana winds can also dry out plants quickly, so be sure to provide adequate water and consider providing some shade during the hottest part of the day, especially inland.

Borage is a great companion plant for many vegetables and herbs. It's known to attract pollinators and beneficial insects, making it a welcome addition to any garden.

Good companions include tomatoes, squash, strawberries, and cucumbers. Borage deters tomato hornworms and other pests that attack tomatoes. It also improves the growth and flavor of strawberries. Borage is said to help squash and cucumbers by attracting pollinators and deterring squash bugs.

Avoid planting borage near fennel, as they can inhibit each other's growth.