Lavandula dentata, the lavender with a bite

Often called French lavender, especially in the United States, Lavandula dentata is a wonderful ornamental shrub.

List of Lavandula dentata facts

Name – Lavandula dentata
Common names – French lavender, toothed lavender, fringed lavender
Family – Lamiaceae

Type – small shrub, herbaceous
Height – 24 to 40 inches (0.6 to 1 m)
Exposure – full sun, fully exposed

Soil – ordinary, very well drained
Foliage – evergreen
Flowering – June to August

It boasts all the great assets of common lavender with the added benefit of showy flowers and cute toothy leaves.

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How to plant Lavandula dentata

Best soil for Lavandula dentata

Soil type is only important in the following respects:

  • very well-draining (slope, rocky, sandy)
  • not too acidic. Prefer neutral or alkaline

Planting Lavandula dentata

The ideal season is to plant in fall. This gives the end of the season for the plant to settle in before the winter.

  • Set the clump in a pail of water while you dig a hole that is three times as wide as the clump.
  • If purchasing a plant with bare roots, make the hole twice as large as the plant itself. Prepare root dip to maximize recovery.
  • Layer some gravel or expanded clay pebbles at the bottom of the hole to maximize drainage.
  • Place the root ball on top of this and backfill with a mix of sand and garden soil.
  • If you didn’t soak the root ball, water abundantly once, but then stop watering. Only if the weather is extremely dry during the first year should you water again.

Exposure

This plant can bear the brunt of hot sunrays in stride. It actually makes the plant more fragrant! Place it in the hottest, driest, sunniest spot of your garden.

Growing Lavandula dentata in pots

The key to helping your L. dentata thrive is to control moisture: aim for none!

Setting up the pot

  • Check that there are several drainage holes at the bottom of the pot, or one very large one.
  • If you must catch the water in a saucer, make sure the pot itself never touches the saucer. Layer clay balls in between to keep the pot from touching stagnant water.
  • Remove excess water shortly after watering.
  • The soil mix used should drain very fast. 50% sand/gravel is perfect, with either garden soil or proper flower pot mix. Best if the sand isn’t too fine, prefer coarse, irregular sand if possible.
  • Mulch the top of the pot with rock mulch so you won’t need to water as much.

Watering fringed lavender in pots

Pots require much more attention than L. dentata growing in the ground (to be honest, when in the ground, watering is never needed).

In pots and containers, however, it’s important to check on moisture often. That way you’ll get a hang of when the plant needs water, and only water then.

  • Stick a finger into the soil at least two knuckles deep. A tongue depressor or ice-cream popsicle stick also works well.
  • Pull it out.
  • Dusty tip: feel free to water.
  • Smeary, moist tip: wait for another three days.

Proper Lavandula dentata care

Winter care for Lavandula dentata

  • In the first year of planting, try to protect your young toothed lavender with hay in case of freezing.
  • After that, in case of severe cold (below 23°F or -5°C), it’s best to winterize your lavender, especially if grown in a pot.

Lavandula dentata fertilizer

In the ground, there is no need to add fertilizer.

In pots, apply any flower-specific fertilizer (low dosage) or prepare fertilizer yourself from weeds.

Lavandula dentata leaves with tiny toothed rim.

Pruning and/or trimming Lavandula dentata

Lavender does not grow back from old wood. Cutting it to the stump would usually kill it.

  • Prune once a year, at the end of winter (fall possible in areas with mild, non-freezing climates).
  • Set reminders in your calendar because yearly pruning is the best way to get perfectly round mounds.
  • With long garden shears, trim the lavender, snipping it into a round shape.
  • Always remain within the leafy section of the shrub. Don’t prune to where stems aren’t bearing leaves anymore.
  • Start pruning when the plant is already young to maximize branching out.

Learn all about pruning L. dentata in this two-minute video

Using Lavandula dentata flowers

Much of the joy of growing L. dentata comes from the long-lasting scent the flowers have. This can be harnessed to make replacement scented softener for clothes!

  • Make small cloth pouches and fill them up with dried lavender flowers. Pick each bud from the stem.
  • Best wait for the lavender to have dried on the stalk. This makes removing them easier. Also, it eliminates any risk of staining when perfectly dry.
  • Don’t put this pouch in the washing machine! Simply place it between clothes when already dried, folded and put away in the closet.

For more fragrance, you can also make lavandula wands. These, oppositely to the grain-filled pouches, are best made from newly opened flowers. Since the ribbons and stems form a loose basket in this project, it’s best when the grains stay firmly attached to the stem.

Protecting Toothed lavender from diseases

Pest-resistant and virtually disease-resistant, too.

Only worry: root rot due to whichever root rot fungus is dormant in the ground or brought along by wandering insects. Rhizoctonia, Phytophthora, Thielaviopsis or Pythium are all possible.

Symptoms

  • Wilting leaves, yellowing as if underwatered.
  • Black streaks on roots and inside branches.
  • Dieback.

Cure

When caught early on, it may still be possible to save the plant.

  • Prune infected parts.
  • Apply natural fungicides such as fermented horsetail
  • Increase drainage. You might need to dig your plant out to do this. Proceed carefully.
  • Stop watering until dry, then only water sparsely.
  • Keep out of rain if outdoors.

Learn more about L. dentata

This wonderful plant brings together two wonderful joys: amazing fragrant flowers and cute, tooth-edged leafage.

It also goes by the name “Butterfly lavender”, mostly because it attracts them but also because of the winged appearance of the flower. It shares this fluttery common name with Lavandula stoechas.

Just like other types of lavender, Lavandula dentata was, and still is, extensively used for perfume, cosmetics and hygiene products.

Its pungent compounds also help repel aphids. They are a welcome addition near tall-growing English roses!

Somewhat uncannily, L. dentata is called “Lavande anglaise” (English lavender) by the French, but “French lavender” by the English and the rest of the world!

Smart tip about Lavandula dentata

After pruning your plant, grow cuttings from trimmings in small terra cotta pots. They will grow and make perfect gifts for family, friends and neighbors!


Credits for images shared to Nature & Garden (all edits by Gaspard Lorthiois):
Blooming Lavendula dentata flower by Don Loarie under © CC BY 4.0
Fringed lavender leaf by Lies Van Rompaey under © CC BY 2.0