Cultivation
Lavender is native to rocky regions with alkaline soil and a lot of sun so it's our job to create conditions to make it feel at home.   If you know or suspect that your soil is leaning toward the acidic side we recommend that you sprinkle a handful of lime (Calcium Carbonate) around the drip line of the plant.   Dolomite or Agricultural, prill or powdered, most forms of lime will do the trick.   It's recommended to lime when you transplant as well, mixing it into the surface soil. You may try this in locations that you've had difficulty with lavender in the past.   Lavender needs full sun to grow densely and have prolific blooms.   In optimal conditions the plant should receive 8+ hours of direct sunlight during growing season.   I have seen many examples of limit pushing when it comes to light but plants receiving 5 hours or less of direct sunlight will be leggy and bloom will be thin. We recommend at the very least 6 hours of direct sunlight and in this exposure it is important that the plant is receiving this in the heat of the day (morning and evening light is, of course, not as intense). Drainage is a very big issue. Lavender, in general, is a pretty tough plant but if there were one weakness that would get it every time it would be poor drainage. Lavender plants should never be planted in situations where the soil or plant will be inundated with water. If you dig a hole and it fills with water at any time of the year, other than during or immediately after a downpour, it is a good indication not to plant lavender there. Here in the PNW we do have very soggy winter conditions so we recommend building raised beds to increase drainage of water away from the plant.   We do recommend a light transplanting fertilizer but lavender in general should not require much more than the soil can provide.   In extreme cases, when plants turn yellow or look like they are struggling this could be the result of not enough water or lack of nutrients.   In this case a fertilizer or more frequent watering should be provided.

Transplanting

Dig holes approximately three times the volume of the pot size you are planting.   This is the time to mix with your backfill, lime, a light transplanting fertilizer if you choose, and to rough the roots thoroughly, without breaking too many off.   Make an effort to keep the majority of the roots pointed downwards when placing the plant in the hole.   It is important that the woody stem of the plant is not covered with soil, planting too deep can often lead to stem rot.   Water the plant in thoroughly and remember when transplanting in summer that it may look wet but the plant may have sucked the immediate soil around it’s roots dry in the first few weeks after transplant.   Now, sit back and enjoy.

Pruning Techniques and Tips  

The most important thing is not to be afraid!  Lavender is a woody shrub so it rarely works to cut the plant off at the ground and expect it to rejuvenate itself from the remaining stem and root tissue.   Plants need to be pruned every year to keep a dense round shape and to ensure a prolific bloom. The only exception to this is the first season growth.  After transplanting, simply cut off the finished flower spikes where it emerges from the leaves of the plant in the fall.   Lavender that has not been maintained will become weak, top heavy, and split (Lovingly nicknamed “Poodle Lavender”).   We often receive questions regarding what to do with these split plants but there is little that can be done after the damage has occurred.   Shape the plant, as best you can, and live with it or start over with a new plant.   Lavender can be pruned any time of year but I highly recommend summer pruning.   After plants have finished bloom, this depends on variety and what region you live in, it’s time for pruning.   Pruning right after or during bloom allows the plant to recover and put on some new growth before winter.   Harvesting early on Lavandula angustifolia (English) varieties will promote a second bloom in most years.   It's hard to do to a plant in the middle of summer, when everything is at its prime, but doing this early ensures that you don't have to look at a cut back lump of twigs in your yard all winter.   When pruning we recommend that you cut the plant foliage back at least half each year. Counting up an individual stem there should be at least three strong individual leaf clusters minimum. It isn't a science but the leaf cluster count should be somewhere between three and six consistently to make a nice round shape. By fall, the leaf clusters will grow into new foliage, hopefully creating beautiful silver mounds for the winter ahead.  Pruning Lavandula stoeches (Spanish Lavender) can be a challenge in that in some seasons it never stops blooming.   Our best recommendation would be to prune it at least once a season (Early Summer is best), removing stray growth and shaping the plant back to a manageable size.   Avoid fall pruning of Spanish lavender and leave plenty of leaf material.   If you feel you have a special situation or question we’re always glad to help you through.

Choosing a Lavender

You've found a great lavender website but there are possibly too many choices.  Here are some questions to ask yourself before selecting Lavender for a specific site.

What is my Zone and Climate Like?

Ask your State extension service or other local gardeners if you don't know what you local USDA zone is.   It is sometimes confusing because maps are general and you may live in a microclimate that is either cooler or warmer than the areas that surround you.  Also consider humidity when selecting plants.

What size Plant do I need or have room for?

Some lavender grow surprisingly large and some can be disappointingly small.   Here are some approximate adult plant sizes of common lavender and spacing to give you an idea of how many plants you may need to fill a space.

Lavandula angustifolia (English Lavender) tend to be 24”tall x 22”wide (space >2.5ft.)

Lavandula x intermedia (Lavandin) tend to be 36"tall x 36"wide (space at >3ft.) Lavandula ang. x lanata hybrids are variable in size (space at 2.5-3ft)

Lavandula stoeches (Spanish Lavender tend to be 24”tall x 36”wide (Space 3-4ft.)

What color am I looking for?

It seems that there are so many varieties that are so alike yet they are all a little different.   One consideration is the overall color effect is derived from corolla color, calyx color and sometimes sterile bracts.   When I select a variety for color I put more weight on the color of the calyx (This is the fuzzy part commonly used to make sachet).   The calyx color is visible before, during and after the corollas open and this color is what will remain when stems are dried.

What am I going to use my plant for?

Lavender is commonly used for the purposes of ornamental, oil production, dry and fresh flowers, sachet, fragrant crafts and in cooking.   Here are the common uses for some different types of Lavender.

Lavandula angustifolia (English Lavender) Landscape, low hedges, oil production, fresh cut and dry flowers, sachet, crafting, and our favorite for use as a culinary.

Lavandula x intermedia (Lavandin) Landscape, hedges, oil production, fresh cut flowers (some work well for dried flowers), sachet, fragrant crafts, often suggested for culinary use but we find it too strong in fragrance and flavor.

Lavandula ang. x lanata (wooly hybrids)   Landscape, low hedges, fresh cut flowers

Lavandula stoeches (Spanish Lavender)   Landscape, hedges, fresh cut flowers

Growing Lavender in Tropical and Humid Climates

This pushes the limit of Lavender but every year we receive requests and recommendations for varieties that will do well in humid and tropical settings, Hawaii and continental South East United States in particular.   Lavender comes from a Mediterranean climate; sunny, rocky and dry.   My best suggestions for cultivation is to be sure plants receive enough soil drainage and that they are in full exposure, Southern or Western is best.   This is important because plants need a chance to dry off quickly after fluxes of summer rain and humidity.   Also choose varieties with smoother and green foliage.   Varieties with silvery and gray-green foliage have a thick layer of pubescence, fuzzy hairs, that will hold water and lead to problems quickly.   An advantage to growing in a tropical/sub tropical climate is plants are confused and will often bloom year round.   

Our best suggestions

Lavandula x intermedia varieties ‘Abrialii’, ‘Blanc Caty’, ‘Fat Spike’, ‘Grappenhall’, ‘Grosso’, ‘Lullingstone Castle’, ‘Provence’ and ‘Seal’

Lavandula heterophylla (Sweet Lavender)

Lavandula minitoulii

Lavandula canriensis

Lavandula dentata varieties ‘Linda Ligon’ and Green Form

Avoid

Any of the Lavandula angustifolia (English) varieties

Any of the L. x intermedia varieties that I did not mention

Any of the Lavandula ang. x lanata (Wooly hybrid) varieties

Growing Lavender in Cold Climates

For those who want to push the limit of their cold climate there is hope with Lavender.   Lavandula angustifolia (English Lavender), in general, is a USDA Zone 5 but can survive winters in Zones 3 and 4 with the proper protection.   I would not recommend Lavender for field production in colder climates but it would make a fine addition to herb gardens or borders.   When choosing varieties, pick ones that are compact in growth habit and grow less than 24” at adult height.   This will help make sure that plants are low and out of desiccating winds and will increase the chance that they will be snow covered during extreme winter low temps.   In cultivation, plant near buildings, walls, larger shrubs or anything that will keep the soil temperature a little warmer, provide shelter from wind, and promote snow accumulation.   Plants can be wintered over in containers but this is a skill learned by experimentation and practice.   Some people just have a knack for it?   Avoid bringing plants inside you living space because low indoor humidity will usually kill plants off quicker than cold temperatures.   Lavandula x intermedia varieties, a USDA Zone 6, have been grown in Zone 5 with some success but expect to lose them in extremely cold years.   Use the same techniques and cultivation ideas mentioned above if you'd like to try.   They can be a little more difficult due to their large size.

Our best suggestions

Lavandula angustifolia varieties ‘Bowle’s Early’, ‘Dwarf Blue’, ‘Dwarf White’,   ‘Hidcote’, ‘Hidcote Pink’, ‘Irene Doyle’, ‘Martha Roderick’, ‘Nana’, ‘Royal Purple’ and ‘Sarah’

Lavandula x intermedia varieties for Zone 5 ‘Grosso’, ‘Provence’, ‘Abrialii’, ‘Champion’s Skylark’, ‘Blanc Caty’

Avoid

Lavandula angustifolia varieties larger than 24”, ‘Potpourri White’ and ‘Lady

Any other Lavandula species

Brief Descriptions of Common Lavender species

LAVENDERS aka LAVANDULA Lavenders are all members of the same botanical genus: Lavandula. There are about 20 species of lavender, and each one is distinguished from another by a different species name. For instance, Lavandula viridis, Lavandula lantana, Lavandula dentata (French Lavender), Lavandula stoechas (Spanish Lavender). Most of the lavenders found in gardens are hybrids or cultivars selected from just a few different species, and fall into two basic groups.

The first are all cultivars of the species Lavandula angustifolia, and are often called ENGLISH LAVENDERS.

The second group is made up of hybrids between the English lavenders and another species, Lavandula latifolia, and are called LAVANDIN.

Both of these groups have grey/green foliage, make nice low shrubs, and are hardy to about USDA Zone 5. They prefer full sun and a well drained soil. All are fragrant, and though the compositions of their essential oils does differ, it is difficult for most people to tell them apart by their scents. The biggest differences between them are in their heights, flower colors, the size of the flower heads, and the time of blooms. The English lavenders tend to bloom in early summer, the lavandins in midsummer. The darkest flower colors are among the English lavenders, while the tallest plants, the longest flower stems, and the largest flower heads are among the lavandins. Many people prefer the English for dried flowers and the lavandins for potpourri, oil production, and the making of lavender wands (dollies). You can use both types for all purposes, and particularly the two darkest lavandins, 'Grosso' and 'Abrialii', as well as the darker English types for dried flowers. It is important to note that the lavender flower is made up of two parts, the corolla and the calyx, each with a different color. The tubular corolla, what we usually think of as the petals, are most often violet colored, though some are white or light pink. The calyx colors range from a very deep purple to a light violet/green. When lavender flowers dry, the corollas fall out or shrivel up and only the calyx color remains. So when you choose a cultivar for dried flowers it's only the calyx color that matters.

Lavandula angustifolia
True Lavender or English Lavender - also known as L. officinalis , or population lavender in France.   Lavandula angustifolia is the hardiest of all types of lavender, most are USDA Zone 5, commonly having narrow silver leaves and a sweet and mild scent. The average size when full grown is 24”high and 22”wide. Usually born on shorter stems (3”-6”) flowers range in colors of violet, purple, blue, pink and white. Spikes are arranged on the stem in whorls with the top of the flower spike being flat in most cases.   Common uses for English Lavender are culinary, fragrant crafting, cut flowers (dry and fresh), fragrant crafting, oil production and ornamental purposes. 

Lavandula x intermedia

Lavandins-   These are a cross of Lavandula angustifolia (English lavender) and Lavandula latifolia (Spike lavender). In the foothills of the Mediterranean, these two species occupy some of the same growing areas in the wild and have cross-pollinated to form a new group of lavenders called Lavandin.   Because they are sterile most all Lavandins are vegetativly propagated.   The leaves are usually longer and broader in nature than that of English varieties and the shrubs grow to 36” x 36” when full grown.   The stems are long (10”+) and usually branched with slender pointed spikes.   Colors range from blue-violet to blue and white.   Lavandins have a much more pungent oil than that of the English varieties making the oil optimal for soaps, crafts, and cleaning products.   Fragrant crafting, sachet, and Fresh and Dry cut flowers are also popular uses for the Lavandin.

Lavandula stoeches
Spanish Lavender-   Native to islands south of France in the Mediterranean and commonly referred to as Italian lavender.   This species has narrow gray leaves and is characterized by its sterile bracts that stick up like ears from its cylindrical spike.   (Some people think they look like colorful bumblebees.)   Plants are bushy with narrow gray-green leaves and have a sweet fragrance.  Most will grow wider than tall (24”tall x 36”wide).   Lavandula stoeches var. pedunculata is a subspecies that has larger sterile bracts and tends to be a little more upright in habit.     Great for rock gardens, borders, and fresh cut flowers and foliage.   Most are a USDA Zone 7 but can survive years in Zone 6.

Lavandula angustifolia x lanata

Wooly Lavender Hybrids-   These have a mounding habit, grow in various sizes and have dense, pubescent foliage of bright silvery-green.   They are one of the few Lavender that have true violet corollas.   Uses include ornamental and fresh cut.   We have used them for crafting but prefer and English or Lavandin.   A USDA Zone 6, avoid growing this variety in humid climates due to its dense pubescent foliage that can lead to fungal problems.

Tropical Lavender

Lavandula dentata , Lavandula minutolii , Lavandula heterophylla , Lavandula pinnata var. buchii and Lavandula canariensis .   Deemed “tropical” because they will die at sustained temperatures below 32 degrees F.   There are always exceptions and microclimates but in general these plants need to be considered annuals in cooler climates or be protected during winter.   This winter of 2005 several plants in full exposure have wintered well with temps, on numerous occasions, having dropped to the low 20’s.   It has been unusually dry and this may have helped them survive?   Uses for these plants are for ornamental, fresh cut, and Lavandula heterophylla can be used for crafting and dried arrangements.   USDA Zone of 8-10.