By Lynne Griffin, Vice Chairman WRHS
If you are overwintering a Rosemary plant, March represents a critical period. This herb has increased needs for both any fresh warm air available (above 40 degrees) and plenty of water. Check the soil daily for moisture and add water as needed (this is not too much to ask as it is only temporary until frost is no longer imminent and your herb can be planted out in a garden location). If the soil does dry out and your Rosemary begins to wilt, add a generous amount of water and check on it the next morning. If it does not respond to watering and perk up, harvest as much of the Rosemary plant as possible before it dies and plan on purchasing a new one in the spring.
Rosemary plants can be set outdoors on warm spring days (temp. above 40 degrees in a protected, shady, calm site). It will need to be brought back inside overnight and anytime the temperature begins to drop.
Also, Rosemary is particularly susceptible to Powdery Mildew during the month of March. Powdery Mildew can be identified by the appearance of a powdery looking growth accumulating on it’s needles. This is due to the herb’s increased need for water and see saw periods of dryness and watering. Again, checking the soil moisture daily with your fingertip can avoid this problem, but not always. Try to keep the soil evenly moist. Included is a recipe for Powdery Mildew that I have used successfully on Rosemary with this problem.
Anti-Powdery Mildew Recipe for Rosemary
1 Gallon water
2 Tablespoons Baking Soda
2 Tablespoons Salad Oil
Mix together and shake well.
Put into a spray bottle.
Shake well before each use.
Spray on affected areas weekly.
Sometimes you can do everything right, follow all instructions, utilize every tip and the Rosemary plant will die anyway. However, don’t give up yet, as there is a back up plan available! Simply buy a new Rosemary plant from your favorite nursery and try again next year.
Experience is a great teacher!