Plant Name:  Lavender, Heterophylla

Common Name:  Sweet lavender

Botanical Name:  Lavendula x heterophylla
Note:  The original heterophylla was probably a cross between two lavenders:  L. dentata and L. angustifolia.  Most heterophylla plants today are actually a cross between L. dentata and L. latifolia.

Origin:  Southern France

Height/Physical Description:  This variety is approximately 24 to 30 inches in height and width, has gray-green leaves with flowers that are bright violet and bloom in midsummer.

Special Attributes:  The leaves are gray-green and mostly smooth edged.  The leaves near the base of the plant are coarse-toothed (dentate) in the middle and near the tip, showing the dentata heritage of the plant.  Sweet fragrance and long flower stems.

Purchasing:  Online and private nurseries.

Planting Requirements:  Plant in Spring after danger of frost or in the Fall.  Lavenders require good drainage.  If soil is mostly clay, amending and aerating the planting area will ensure better success.  Planting in a dome is another way to promote good drainage and keep your lavender from sinking down in clay soil.  The preferred mulch at the base of the plant is gravel or a thin layer of compost.  Do not use wood or leaf mulches as this contributes to root rot.

Repotting and transplanting:  To determine your lavender is hardy and ready to repot or transplant, check the bottom of the container for vigorous roots coming out of the drainage holes.  This is a sign of good health.

Watering:  Water at base of plant only.  Lavenders do not like overhead spray.  Use of a drip system is best. Put on a drip line with plants that have similar water needs to avoid overwatering.  Lavenders rot very easily when overwatered.  To avoid this, allow the soil to dry out moderately before next watering.

Fertilizing:  Lavenders are hillside plants that thrive in rocky, good draining soil that is somewhat alkaline (pH of 6.5 to 7.5).  Lavenders do not require a great deal of fertilizer as they prefer neutral soil.  Since this is the case, use of compost or compost tea is all that is needed.

Blooming Time/Harvesting:  Bloom starts in midsummer.

Pruning:  Lavenders can live up to 25 years if well maintained.  The time to prune is after the flush of flowers.  The flowers and stems should be gently pruned so the plant is the shape of a ball. Consider it a haircut not a severe pruning.  Removing the flowers in this manner allows the plant to regenerate foliage and avoids it from becoming “woody.”  

Note:  If the plant has become woody, it cannot be reversed.  It will live but will not have the original full shape that it had at the beginning.

Pruning underneath the plant is another way to keep the plant healthy as this promotes good air circulation which prevents root rot.

Pests:  Spittle bugs, grasshoppers, gophers, moles.

Diseases:  Root rot.

Hardiness:  zones 8-10
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Additional Comments: This plant is slightly cold hardy.  Protect from frost to be safe.