Growing Rosemary

Latest Update 29th July 2016.

Rosemary
  • I grow rosemary as a culinary herb, as habitat for predatory and pollinating insects, and as an attractive herbaceous border plant.
  • The photograph shows one of my rosemary plants growing healthily in the under-story of my olive tree with a number of other herbs and flowering perennials.
  • Rosemary propagates easily from cuttings, and I strike a few each winter in my cuttings propagator.
  • They are perennial and if you give them a haircut each spring, they will stay compact and look good for many years.
  • Rosemary is a main component in my dried herb mix preserved in glass jars.  I use it all the time on steamed and roast vegetables, but its a useful flavouring in preserves and meat dishes. 
  • I find rosemary is usually pest free in my garden.
Details.
  • Variety:                                                  Rosmarinus Officinalis. 
  • Family Group:                                         Lamiaceae. 
  • Garden bed type:                                     Drip line irrigation.
  • Recommended Soil pH.                            7.0 - 7.8.
  • Minimum Sun per Day:                             3 hours.
  • Plant Spacings (centres):                         500mm.  
  • Climate:                                                  Warm Temperate. 
  • Geography:                                             Southern Hemisphere. 
Nutrition.
  • This food is low in Sodium, and very low in Cholesterol.
  • It is also a good source of Vitamin B6, Magnesium, Potassium and Copper, and a very good source of Dietary Fibre, Vitamin A, Vitamin C, Folate, Calcium, Iron and Manganese.
  • More from nutrition data.self.com. 
Growing Conditions:
  • Rosemary grows best in full sun. 
  • It prefers sandy soil but grows well in most healthy organic soils. 
  • It grows well in hot dry conditions. 
Soil Preparation. 
  • Select a space for your new plant where rosemary has not been grown for some time.  Clear previous crop residues and mulch and add a 60mm top dressing of homemade compost.  Cover with a 50mm thick layer of straw mulch.
  • Leave the bed for 4 weeks to build up worm and microbial activity.
Growing Instructions. 
  • My original rosemary plants were grown from seed, but it is so easy to propagate from cuttings, that I no longer buy or save seed.
  • To do this, choose your strongest most vigorous plant as a source.
  • Take 100mm long cuttings from your strongest most vigorous plant as it starts to grow in spring.
  • Remove the lower leaves except for those in the top 15mm of the cutting.  Plant the cuttings 50mm deep in a propagator.
  • The propagator's compost layer and constant moisture stimulates root growth, so I don't need to use rooting powder.
  • Once the cuttings start to grow vigorously, move the mulch on your prepared bed out of the way and transplant them.
  • Water them in and keep the soil moist until they are established.  Replace the mulch but keep it away from their stems.  Follow up with a foliar spray of aerated compost tea every 4 weeks.
  • If left to its own devices a rosemary plant will become woody after a couple of years, however, regular pruning will extend its productive life to 4 years. 
  • You should prune the established plant in spring after flowering.  Remove the flowers and cut the green growth back by 1/3rd.  Do not cut back into old wood. 
Harvesting and Storage. 
  • Rosemary can be harvested at any time, but don't strip too many leaves at once or you could check the plant's growth.  Its best to maintain several plants and harvest a few stalks from each plant.
  • Begin using the leaves as soon as the plant is large enough to spare some.
  • You can air-dry rosemary in small loose bunches hung in a cool, dry, dark place or dry them in a dehydrator.
  • Once the leaves are dry, strip them from their branches and crush them (I use a mortar and pestle).  Store them in an airtight glass container ready for use.
  • I premix them with dried thyme, sweet marjoram, sage, basil and oregano before use.
Organic Pest Control. 
  • Slugs and snails.
    • To keep slugs and snails at bay, I grow my herbs in a drip irrigated raised bed, and run copper tape around it 100mm off the ground.
    • Copper tape is a very effective barrier as the slugs and snails get a small electric shock when they come into contact with it, and they retreat to less hostile surroundings.
    • Occasionally I get one or two juvenile snails in my raised beds.  I believe they get into the bed as eggs though the compost heap.  When this happens, I use a few iron chelate snail baits to round them up.  Only use the bare minimum to do the job.
    • Aerated compost tea strengthens the plants foliage against whitefly damage.  
    • Control any infestations by spraying your crop thoroughly with organic horticultural oil (Eco-oil in Australia).
    • Spray again in a few days to ensure second generation whitefly do not survive.
    • Use the same method as described above for whitefly.
  • General:
    • Regular applications of aerated compost tea boost the natural defences of plants by colonising the leaf surfaces with beneficial microbes.  They defend the plant against airborne pests and diseases.
    • Similarly, proper soil preparation including regular applications of home made compost boosts the community of beneficial microbes, which defend the plants roots against plant pathogens.