Common name: English Lavender
Lavandula angustifolia grows in clumps ranging in height from 500-750mm (18"-30") with a spread of around 500mm (18") subject to its location.
This height and spread makes it a useful subject to form a low hedge.
Lavenders will also grow quite well in containers but as they are deep rooted the pots will have to be quite large.
The flowers appear from late Spring right through to late summer.
The variety stoechas is also quite common in the UK but are not as easy to grow due to wet winter conditions.
For this reason they are better treated as container plants which will allow you to move them undercover during the winter months.
Lavender is of mediterranean origin and as such, they prefer sunny conditions, and soil that drains well and is slightly alkaline.
If your soil is quite heavy, improve the drainage qualities by digging in as much well-rotted compost as possible.
Used mushroom compost with its high lime content is ideal.
Lavender is used to scent many products e.g. soaps and perfumes.
To make scented lavender bags (pot pourri), harvest the spikes as they mature (circa week 32), and hang them up in paper bags in a cool airy position to dry.
Tradition dictates that flowers are best harvested about mid-morning to mid-day when the sun has had time to dry off any surface moisture and fetch out the fragrance.
Lavender foliage is well adapted to preserving moisture during dry periods, meaning, that unless there is a prolonged drought and the plant is wilting then there is no need for watering.
Lavender in pots and tubs will require watering a little more frequently but sparingly,and kept on the dry side over winter.
Only water when the compost has dried out.
Do not attempt to prune in a plants first year of growth.
Each year thereafter prune off the top 150mm (6") of growth once flowering has finished in autumn.
In exposed cold areas leave hard pruning of straggly growth until circa week 16.
The straggly growth will give protection to new spring growth.
If after about five or six years of growing, the plants begin to get woody at their bases, and the foliage progressively begins to appear only at the top of the plant,it is best to replace the affected plants.
Pests and Diseases:
Lavenders are relatively free from pests and disease.
Occasionally they may become affected by cuckoo spit (caused by froghoppers / green capsid bug).
Apart from being unsightly, this causes no damage at all.
Clip hedges to desired shape, and hard prune straggly growth on shrubby plants.
If more stock is required pot up a few heel cuttings prior to trimming and place them in a cold frame to root.
Sow commercial seeds in pots/trays of seed compost and lightly cover, then germinate at 18°-20°C (64°-68°F).
Germination should take around two to three weeks.
When seedlings are large enough to handle prick them out into individual 70mm (3") pots of potting compost.
Gradually harden them off by growing them on in a coldframe until planting out time.
Propagate small lavender plants by lifting small plants out by the roots and planting the entire lower half of the plant below soil level.
Established plants do not usually transplant, it is better to replace, or take cuttings.
Take 75-100mm (3”-4”) cuttings of non-flowering shoots and insert in a 50-50 mix (by volume) of compost/peat and sharp sand.
Place in a cold frame to grow on, and plant out the following autumn.
Alternatively select a long stem and gently bend it down to ground level.
Peg it onto ground with a hoop shaped piece of wire and cover with 25mm (1") of soil.
The layer will produce growth the following spring.
Once rooted sever the stem from the parent plant and pot into compost as described above and grow on until planting out time later that year.
Transplant into its final position in early autumn.
Plant out between now and March in an ordinary, well drained soil, in full sun, 600mm (24") apart.
Plant them to the same depth as they were grown in the pot or nursery bed.
As you are planting them,remove all flowers and trim the longer shoots down to the same level as the lowest shoots.
This will make for tidier growth and it will encourage root growth.
Do not feed lavender when planting it, wait until the following spring.
Each spring apply a general purpose liquid feed, no further feeding is required during the rest of the season.
Avoid high nitrogen fertilisers as these encourage foliage at the expense of flowering.
When forming hedges set plants out 300mm (12”) apart.
Although they are drought tolerant plants, they will need watering regularly until they become established, then they can be left to their own resources.
Divide established plants if required and plant out the divisions immediately.
Remove faded flowers from established plants and lightly trim plants.
If more stock is required, collect and sow ripe seed (they should be dry and black) and sow and germinate them as described above (Week 16).