Rosemary is one of the toughest shrubs in the garden and a great evergreen plant to anchor a summer dry bed. It is from the Mediterranean Basin and is well suited to our climate. There are many different varieties and forms, some tall, others spreading. Flower color can also vary from pale blue to deep blue, and less commonly, pink and white. The variety in the Palo Alto Demonstration garden is 'Tuscan Blue'.
Rosemary starts blooming in the winter and provides food for bees when little else is blooming. Rosemary sometimes has a small bloom in the late summer and fall as well.
The 'Tuscan Blue' rosemary shrubs in our Palo Alto Demonstration Garden have never grown taller than 4 feet and are more ball shaped than vertical. Part of this may be due to less watering and part of this may be due to our pruning regime. We prune it by 1/3 to 1/2 after it finishes blooming in late spring to control its height. We also prune side branches that fall on other plants. Once the plants become mature, we prune out up to 1/3 of the large woody branches to control plant size and maintain vigor.
To minimize pruning, we have taken out several of our 'Tuscan Blue' rosemary shrubs and replaced them with the smaller cultivar 'Mozart', a UC Davis Aboretum "All-Star". We'll let you know how are experiment works.
Rosemary is useful herb in the kitchen.