Borage in Zone 9A — Desert Southwest

Borage is a fantastic addition to your Desert Southwest garden, offering edible cucumber-flavored leaves and beautiful star-shaped blue flowers that attract pollinators. Imagine adding fresh borage leaves to your summer salads or using the flowers as a striking garnish – a real treat after a long, hot day!

While our extreme heat and arid conditions can be challenging, borage is surprisingly adaptable, especially when planted at the right time. With our long 298-day growing season, you'll have ample opportunity to enjoy this herb in both spring and fall.

You can transplant borage outdoors in the Desert Southwest from early February through early March. Before planting, be sure to harden off your seedlings by gradually exposing them to outdoor conditions for about a week. This helps them adjust to our intense sunlight and temperature swings.

Space your borage plants about 12-18 inches apart to allow for good air circulation. Keep an eye on the forecast for any late-season cold snaps, and be prepared to cover your young plants if temperatures dip near freezing.

Direct sowing is the preferred method for borage, and luckily, it thrives when sown directly in the ground. You can direct sow borage seeds from mid-February through early October in our region, taking advantage of both our spring and fall growing seasons. Borage is known to self-seed readily, so be prepared for volunteer plants in the future!

To direct sow, prepare your garden bed by loosening the soil and amending it with compost. Borage prefers soil temperatures between 60-70°F for optimal germination. Sow seeds about 1/4 inch deep and 12-18 inches apart. Keep the soil consistently moist until seedlings emerge, which usually takes about 7-14 days.

Borage needs moderate watering to thrive in our arid Desert Southwest climate. During the hottest months, you'll need to water more frequently, while in the cooler months, you can reduce watering. The key is to monitor the soil moisture and adjust your watering schedule accordingly.

A good rule of thumb is to check the soil moisture about 2 inches deep using the "finger test." If the soil feels dry, it's time to water. Aim for about 1 inch of water per week, delivered at the base of the plant to avoid wetting the foliage, which can encourage powdery mildew in our warm nights. During monsoon season, let the rain do the work for you!

Signs of underwatering include wilting leaves and slow growth. Overwatering can lead to root rot, indicated by yellowing leaves and a generally unhealthy appearance. Mulching around your borage plants with organic matter like wood chips or straw helps retain moisture and regulate soil temperature, a valuable practice in our climate.

You can expect your first borage harvest around mid-April if you plant in February, and harvesting can continue through mid-December. Look for the star-shaped blue flowers to be fully open – these are a great indicator that the plant is ready to harvest. Young leaves are also edible and have a refreshing cucumber-like flavor.

To harvest, gently snip off the flowers or leaves with scissors, being careful not to damage the plant. Regular harvesting encourages continued production. As the first frost approaches in early December, you can harvest any remaining leaves and flowers to dry or use fresh.

Here are some common problems you might encounter growing borage in the Desert Southwest:

Self-seeding aggressively

• What it looks like: Borage seedlings popping up everywhere in your garden, even in areas where you didn't plant them.
• What causes it: Borage is a prolific self-seeder, and the seeds can easily spread throughout your garden. Our mild winters allow many of these seeds to germinate.
• How to fix/prevent it: Deadhead the flowers before they go to seed to prevent unwanted seedlings. You can also pull out any volunteer plants that you don't want.

Powdery Mildew

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

Can become leggy

• What it looks like: Long, spindly stems with fewer leaves and flowers.
• What causes it: Insufficient sunlight or overly rich soil can cause borage to become leggy.
• How to fix/prevent it: Ensure your borage plants receive at least 6 hours of sunlight per day. Avoid over-fertilizing, as this can promote excessive vegetative growth. Prune back leggy stems to encourage bushier growth.

Desert Southwest Specific Challenges: Our extreme heat can stress borage plants, making them more susceptible to powdery mildew. The arid humidity can also cause the leaves to dry out quickly, so consistent watering is essential. Monsoon rainfall can be a blessing, but it can also contribute to fungal diseases if air circulation is poor.

Borage is a great companion plant for many garden vegetables in the Desert Southwest. It attracts pollinators, which can benefit tomatoes, squash, and cucumbers. Planting borage near strawberries can also help deter pests.

Avoid planting borage near fennel, as it can inhibit its growth. Other than that, borage is a pretty easy-going companion in the garden.