Lavandula pinnata: Unveiling the Beauty of Feathered Lavender

The Lavandula pinnata is a shrub from the Lavender family, standing 30-100 cm tall. It has bi-pinnate deeply lobed leaves that are grey-green in color.

The plant spreads out and blooms deep purple tubular flowers with darker lines, featuring two-lipped petals with the upper lip more developed than the lower.

While the leaves carry a pleasant fragrance, the flowers are scentless. It blooms all year round, but its main flowering period is from November to May or June of the following year. During summer, if the weather becomes too hot, it ceases blooming and enters dormancy.

Originally from the Canary Islands, it is widely cultivated around the world. It thrives in full sunlight but needs shade during the summer. It has a good heat tolerance, but requires good drainage and sunlight. It’s semi-hardy in nature.

Feathered Lavender plants are often used in landscaping, placed amongst trees and shrubs as ground cover, transition zones for lawns, along roadsides, garden squares, and other such environments. They contribute to a visually pleasing aesthetic.

I. Morphological Characteristics

The Lavandula pinnata is a perennial herb, standing 30-100 cm tall. The whole plant is densely covered with white fuzz. The leaves are bi-pinnate, deeply lobed, and covered with a powdery substance giving them a grey-green appearance.

The plant spreads outwards, with leaves that are linear or inverted lanceolate shaped. The leaves are deeply lobed, giving them a feathery appearance.

The flower stems are long, with inflorescences around 10 cm, and are purplish-red in color. The upper lip of the small flowers is larger, and the base of the flower spike grows a pair of branched spikes, giving it a trifurcate appearance.

The deep purple tubular flowers have darker lines, and two-lipped petals, with the upper lip more developed than the lower. Its fragrance is a strong mix of geranium and rosemary, but it also has a heavy undertone.

While the leaves carry a pleasant fragrance, the flowers are scentless. It blooms all year round, but its main flowering period is from November to May or June of the following year.

During summer, if the weather becomes too hot, it ceases blooming and enters dormancy.

II. Distinct Features

Feathered Lavender and Pinnate Lavender are quite similar. The main distinctions lie in the fact that Feathered Lavender has a more upright plant habit suitable for pot cultivation, with shorter fuzz on its leaves and less noticeable bi-pinnate leaves.

On the other hand, Pinnate Lavender has a plant habit that leans upwards and is more suitable for beautifying courtyards. It has longer fuzz on its leaves and its bi-pinnate leaves are more noticeable.

III. Origin and Habitat

Feathered Lavender originates from the Canary Islands and is widely cultivated worldwide. It’s a full sun plant that requires good sunlight exposure. It grows poorly in shaded areas but needs to be shaded during the summer.

It’s robust, heat-tolerant, semi-cold resistant, and prefers well-ventilated conditions. A sandy loam soil rich in organic matter is optimal for its cultivation.

IV. Propagation Method

Seed Propagation

• Dig 15 centimeters deep into the soil to be planted and mix the excavated soil with decomposed leaf soil and river sand, then fill it all back in. The volume ratio of the soil, decomposed leaf soil, and river sand should be 5:3:1.
  
  The decomposed leaf soil is formed by the decomposition of broad-leaved forest leaves after they fall and get soaked by rain. The river sand should have a particle diameter of 0.5 millimeters.
  
• After filling, sprinkle 41 kilograms of Pentachloronitrobenzene per acre over the soil to be planted, then mix and rake the top 5 centimeters of soil smooth to prevent the occurrence of collapse and wilt diseases.
  
• After raking, sow the Feathered Lavender seeds on the soil. After sowing, cover with a layer of turf charcoal soil with a thickness of 1 millimeter.

Tissue Cultivation

Cultivation conditions: The stem segments of annual branches of the Feathered Lavender are used as explants. The basic medium is MS medium, which contains 30 grams/liter of sucrose, 9 grams/liter of agar powder, with a pH value of 5.78-5.8.

The culture room temperature is (25±2)℃, the light exposure time is 12 hours/day, and the illumination intensity is 25-30 micromoles/square meter/second.

Cultivation methods:

• Sterilization treatment of explants: Cut the stem segments of Feathered Lavender into small sections of about 2 cm with nodes, remove the leaves, wash for 5 minutes with 500 times diluted detergent, rinse with running water for 1 hour, and then sterilize with 0.1% mercuric chloride.
  
  During sterilization, give 6-8 minutes of sterilization time. After washing 4-5 times with sterile water, cut off a small part of the stem that directly contacts the mercuric chloride at the cut, and inoculate it on the MS medium containing 0.5 mg/liter 6-BA and 0.1 mg/liter NAA for primary culture, with 1 explant per bottle.
  
  The Feathered Lavender explants have good cultivation effects in this medium, which is supplemented with 0.5 mg/liter 6-BA and 0.1 mg/liter NAA.
  
• Propagation culture: Using MS as the basic medium, 16 combination media containing 0.4, 0.8, 1.2, 1.6 mg/liter 6-BA and 0.05, 0.1, 0.15, 0.2 mg/liter NAA are designed.
  
  The sterile primary cultures are transferred to these 16 media, with one per bottle, each treatment with 18 bottles. After 42 days, we observe the induction and growth of the clustered seedlings and record the culture results.
  
  The multiplication factor obtained on the 16 hormone ratio media is 7-19.2. Considering the convenience of operation and the robustness of the clustered seedlings, we find it appropriate to use the MS medium supplemented with 0.8 mg/liter 6-BA and 0.10 mg/liter NAA for subculture multiplication, where the multiplication factor is 11.3, rather than using the medium with a high multiplication factor of 1.6 mg/liter 6-BA and 0.05 mg/liter NAA.
  
  Test tube seedling rooting cultivation is relatively easy. In the screening of the root culture medium of test tube seedlings, we believe that the 1/2 MS medium supplemented with 0.2 mg/liter NAA is better.
  
• Rooting culture: When the clustered buds grow to about 2 cm, they are cut into single plants and transferred to a medium of 1/2 MS (sucrose is also halved to 15 grams/liter) supplemented with 0.1-0.4 mg/liter NAA, with 3 plants per bottle.

V. Cultivation Techniques

Transplantation: When the root of a test tube seedling reaches approximately 0.5 centimeters, move the culture bottle to the greenhouse for seedling hardening for three days. Then, open the bottle cap and continue the hardening process for another 2-3 days.

Remove the seedling, wash away the culture medium from the root with clean water, and transplant it into a mixed substrate of grass charcoal, perlite, and vegetable garden soil at a volume ratio of 1:1:1. After transplanting, spray with a 1000-fold liquid of 50% Carbendazim wettable powder.

Maintain a temperature of 20-30°C and a relative humidity of 60-80% in the greenhouse. After three weeks, water and ventilate normally, gradually transitioning the seedling from artificial control conditions to natural environmental conditions.

Light: Feathered Lavender is robust. Excessive light can cause lignification, but this is less obvious than other varieties.

Temperature: In winter, protection is needed below -5°C. It does not tolerate heavy snow.

Placement: Usually placed in a ventilated area, there is a risk of sudden death if placed indoors or in a damp place in summer.

Cultivation Season: In southern China, the high temperatures and heavy rainfall after May each year are generally not conducive to the growth of lavender. Feathered Lavender is easy to grow in the fall, winter, and spring, so it is less commonly planted in summer.

If it is placed under a rainproof plastic cloth and slightly shaded environment in summer, the plant can still grow well and bloom. For a full and symmetrical plant shape, moderate pruning is needed.

VI. Main Value

Feathered Lavender has a very high flowering rate and a long flowering period. Continuous flowering between mature plants often forms a vast sea of purple flowers, creating a beautiful scene.

It is a popular ornamental plant in Europe and has become an indispensable landscape plant in some leisure farms or herb restaurants in southern China.

Placed in trees, shrubs as ground cover, transitional zones of lawns and roadside, garden squares, and other environments such as flower beds, flower belts, flower clusters, etc., it has a good ornamental effect.