Santolina rosmarinifolia (Green Santolina)
Santolina rosmarinifolia, commonly called Green Santolina or Holy Flax, is a small, aromatic, evergreen shrub with a compact cushion form. It has thin, dissected, bright green leaves and long, wiry stalks bearing yellow button-like flower heads.
It is a drought-tolerant shrub native to the Mediterranean basin, more specifically to the Iberian Peninsula, ie, Spain and Portugal.
HEIGHT & WIDTH
Green Santolina scientific name
- Botanical name: Santolina rosmarinifolia (san-toh-LEE-nuh rose-ma-ree-nee-FOH-lee-uh)
- Family: Asteraceae (ass-ter-AY-see-eye)
- Common name: Green Santolina, Green Lavender Cotton, Holy Flax
- Synonym: Santolina virens, Santolina viridis
|Derives from the Latin words sanctus linum meaning holy flax, referring to the “miraculous” healing properties of these plants.
|Derives from Latin words Rosmarini = Rosemary, folia = leaf, meaning to have leaves like Rosemary
How to identify Santolina rosmarinifolia
Small, aromatic evergreen shrub with a compact cushion shape. It has bright green leaves and solitary yellow flower heads at the tip of long stems.
It has upright stems in the middle and slightly curving stems on the edges.
The shrub has an average height of 60 cm ( 1.9 ft) and a width of 60 cm (1.9 ft)
This species varies widely in terms of leaf size and hairiness.
The stems are more or less straight, i.e., upright in the middle and slightly curved at the edges. They are green and hairless.
The stems have alternate, pinnate leaves, with tufts of smaller leaves at the axils.
The flower stems are long and slightly thickened at the base of the yellow inflorescence.
The leaf is strongly aromatic, dark-green, hairless, and sessile or short-stalked.
The form is pinnate, where the lobes are cylindrical segments with pointy ends, usually arranged in 4 rows, giving it a three-dimensional look.
The main leaves have spaced lobes, whereas the axillary leaves have more densely packed lobes resembling small warty projections.
The overall shape of this composite leaf is linear.
The size of the main leaves varies between 15 and 22 mm ( 0.59 and 0.86 in) long and 1 and 5 mm (0.03 and 0.19 in) wide. The axillary leaves are smaller.
The inflorescence has a capitulum form (button-shaped) and varies between 8 to 20 mm (0.31 to 0.78 in) in diameter. It is composed only of disc florets. There are no ray florets.
The tiny bright-yellow flowers (disc florets) are tubular and have five petals fused at the base. They are held in a tight bundle enclosed by rows of involucral bracts. The stamens and pistil stick out from inside the corolla.
An interesting fact is that the Santolina flowers mature centripetally, i.e. the outer flowers are older and open earlier than the inner ones. That is why the flower button has a darker colour in the centre.
The button-like yellow flowers sit on the tip of long thin stalks and bloom in the summer.
Santolina rosmarinifolia Usage
This shrub is very pretty, and its dark green leaves make a nice contrast with the grey and silver leaves of other shrubs that have the same hardiness and drought tolerance. During the summer, its long flower stalks rise above the foliage carrying bright yellow button-like flowers that create a spectacular effect.
It can be used as a solitary plant or planted in groups. Can be planted in pots, beds or borders. In rock or gravel gardens.
Its compact form that can be easily trained makes it an interesting plant to be used as a hedge.
It is also very popular for seaside gardens because of its resistance to salty water sprays.
This Santolina has been used in folk medicine to treat gastrointestinal problems, dermatitis and insect bites.
The essential oils of Santolina rosmarinifolia are used in the production of perfumes and cosmetics.
The stems and leaves of Green Santolina smell and taste like pickled olives having many culinary uses.
You can add it to salads, pasta, pizza, mushrooms and baked potatoes. But this herb loses most of its aroma when cooked, so it must be added only at the end of cooking. Also, when dried, it loses most of its flavour, so it is preferable to use it fresh.
It can also be used in cocktails to give a savoury taste to the drink
The flowers are used for herbal tea.
The flowers of this shrub are attractive to bees, butterflies and other pollinating insects, which then attract other wildlife such as birds, enhancing the biodiversity of your garden.
Cotton Lavender has been used for a long time as an insect repellent.
- In closets and drawers to repel cloth moths
- In pet kennels and or sleeping baskets to repel ticks and fleas.
- Planted near other vegetables to repel harmful insects
Santolina rosmarinifolia habitat
This shrub grows in the typical Mediterranean landscape at altitudes from 250 to 1900m (820 to 6233 ft).
It is seen in dry, rocky and sandy areas. Scrublands and coastal areas. It also grows in thickets and forest clearings.
How to care for Santolina rosmarinifolia
This shrub is moderately hardy, tolerating some frost and temperatures down to -12ºc (10ºF), as long as the soil is well drained.
However, until it is fully established, it will need winter protection. Add some mulch to protect the roots from low temperatures and the foliage from the wet soil.
It needs full sun (at least 6 hours per day) to maintain its best colour and compact shape. It can tolerate part shade, but it will become more floppy as the stems lose their firmness when deprived of sunlight.
It likes poor, well-drained to dry, stony or sandy soils. If the land is fertile, the shrub tends to become leggy, produce less essential oils and has more difficulty tolerating drought and cold temperatures.
It especially dislikes wet soil, which makes it more exposed to fungal diseases and can lose its compact form, opening up in the centre.
It grows well in most types of soils: mildly acidic, neutral and mildly alkaline.
Once established, Green Santolina is drought tolerant and can go for some time without water (about 4 months if the temperature is not too hot). Overwatering will probably kill it.
During the first two years after planting, you will need to water the young Santolina every two to three weeks during the summer. Allow the soil to dry out between watering. In case of a heat wave, water more frequently. Monitor your plants closely and look out for any signs of stress.
To preserve the soil´s moisture, you should add mulch around the root area of the plant (but not too close to the base). Wood chips and gravel are good options for mulching.
Green Santolina can tolerate strong winds and maritime exposure, adapting to coastal conditions.
The best season to plant is during Autumn, so it will have all winter to develop its roots. In very cold areas, it is best to plant during the spring as long as there is available water throughout the summer to develop its roots.
How to prune Santolina rosmarinifolia
Green Santolina needs to be pruned a couple of times during the year to remain vigorous and compact.
Ideally, you should give it a hard prune in early spring to encourage new growth and prevent it from becoming too woody or splitting apart. Then a light prune in late summer after flowering to encourage bushiness.
Be careful to always prune above the leaf, as the stems will not regrow if it is cut back too hard.
How to propagate Santolina rosmarinifolia
You can also propagate by sowing seeds in a cold frame in autumn or spring. There is a great article about seed propagation at NC Extension.
Other Santolinas you may also like
Sources of information used for this article
Article from Kew
Article from NC Extension Gardener
Models for 3D images from https://www.gbif.org/occurrence/gallery?taxon_key=3125944
Vol XVI from FloraIberica
Field Guide to the Wildflowers of the Western Mediterranean, Second edition Paperback – 1 Oct. 2021 by Chris Thorogood