Well, it makes sense to look at the size and maturity of the plant, doesn't it? When harvesting or pruning (both of which are 'taking cuttings'), just remember never to remove more than one-third of total growth at any one time, then wait for the plant to regenerate before taking more.

From one mature 'branch' of lavender, you can get many cuttings - or you can use the entire branch as a single cutting.

I prefer to take heel cuttings for woody plants like lavender or rosemary.

http://images.google.com.au/imgres?imgurl=http://www.dkimages.com/discover/previews/774/189200.JPG&imgrefurl=http://www.dkimages.com/discover/DKIMAGES/Discover/Home/Gardening/Ornamentals/Shrubs/Propagation/Cuttings/Cuttings-16.html&usg=__MTt0lmsoEHZnYPH6P_NQibuOR68=&h=409&w=424&sz=30&hl=en&start=12&um=1&tbnid=P7lEI7OE0qobpM:&tbnh=122&tbnw=126&prev=/images%3Fq%3Dheel%2Bcuttings%26um%3D1%26hl%3Den%26client%3Dfirefox-a%26channel%3Ds%26rls%3Dorg.mozilla:en-GB:official%26sa%3DN

Here is a link that might be useful: heel cuttings

Purchasing lavenders can be very expensive. Try Possum Creek Herbs for really excellent plants at very inexpensive prices. We bought 500 (!) lavenders from them last year and were extremely happy with the quality, size and price.

Seeds will germinate in 2 to 3 weeks at 75F.
Cuttings from side shoots in late summer or fall will have the best chance of surviving--use a cold frame. If you do cuttings now be sure to protect them when the weather warms up--the first year the plant is working to establish roots so avoid undue stress.

Here is a link that might be useful: HarvestToTable.com

I want a lavendar border on one 12 ft side of the garden, between the raised beds and sidewalk. I am hoping that 5 or 6 plants will do the job and fill in. What do you think? I'm going to use lady lavendar.