Botanical Name:  Lavendula angustifolia “Imperial Gem.”

Origin: Norfolk Lavender, Norfolk, England, 1960’s.

Height/Physical Description:  This plant variety is 24 to 30  inches in height and width, stem length 10 to 14 inches, with dark  blue flowers, gray-green leaves.

Special Attributes:  This variety has dark blue flowers that bloom once in early Spring on 10 to 14-inch stems.  The plant size is compact and easy to manage in residential gardens.    

‍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:  Dark  blue flowers that bloom once in Spring. Harvest when flowers first pop open.

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 5-9

Additional Comments:  Imperial Gem  is a type of lavendula angustifolia.  Angustifolias are considered “true lavender” and known for being some of the most cold-hardy varieties.  Their colors seem more vibrant, flowers seem more fragrant and taste sweet.  A common name that is used for Angustifolias is “English” lavender.  This is not an accurate term especially since lavenders are grown worldwide.  The best way to identify a lavender or any plant in general is by using its botanical name.

Botanical Name:  Lavandula x intermedia, “Impress Purple.”  The “intermedia” lavender varieties are cross breeds.  This means they are a cross between two varieties of lavenders:  L. angustifolia and L. latifolia.  Intermedias are also known as “lavandins”.  These plants tend to grow larger, produce numerous long flower stems, have a high oil content and are hardy.

Origin:  France via New Zealand, 1983; named by Peter Smale, Redbank Research Centre, New Zealand, 1994.

Height/Physical Description:  This plant variety is 30 to 36 inches in height and width, gray-green leaves, purple flowers.  The flower stem length spans 20 to 24 inches.

Special Attributes:  Purple flower spikes that appear brushed with silver when light shines on it.  Great for fresh flower bouquets.    

‍Purchasing:  Private nurseries and online.

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 watering next.  

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:  Purple flowers once in early summer.  Harvest when flowers first pop open.

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 5-9.  

Additional Comments: Intermedias thrive in dry summer climates.  In wetter climates, this lavender is more prone to root rot.