Wednesday, April 14, 2010


Rosemarinus officinalis
An attractive, fast growing, evergreen shrub native to the Mediterranean region of Europe and far northern Africa, reaching up to 6.5 x 6.5 feet in 10 years, and an eventual maximum size up to 8 x 13 ( often much smaller even if not sheared ) feet. Very old plants may develop a short rugged trunk.
It is one of only 2 species of plants belonging to the genus Rosmarinus, that are distant relatives of the Mint family. Rosemary makes an excellent landscape plant as well as an informal hedge.
The rolled, leathery, linear leaves, up to 1.5 x 0.4 ( rarely 2 x 0.8 ) inches in length, are deep green above, silvery to white felted beneath.
The aromatic foliage is used as a herb that is excellent for flavoring lamb, chicken, pork, potatos and soup. If you enjoy savoring tasty cuisine, then the Rosemary is a plant you cannot be without.
The plant is covered in clusters of attractive blue flowers, up to 0.5 inches in length, during late spring and early summer. The flowers are borne on year old wood.
Generally Rosemary is hardy as a shrub only from zone 8 to 10, however there are exceptions with some of the cultivars listed below surviving and thriving outdoors as far north as zone 6. In zones 5 and colder, there really are no options to growing Rosemary unless you grow them in pots during mid spring through mid fall, then bring them indoors for the winter ( often even a cool greenhouse will work ). All Rosemary prefers a hot dry site with soil of any texture and PH as long as it is WELL DRAINED!!! Full sun is also required. Rosemary does not like soil that is excessively wet and waterlogged, especially in winter. Rosemary can survive without irrigation in regions with as little as 10 inches of yearly precip or rainfall. In fact, in much of its native range including Spain, Italy and Greece, summer brings no rain at all.
Rosemary can be pruned after flowering to preserve a dense, bushy habit.
Rosemary is rabbit and deer resistant. Pest and disease problems are rare.
Propagation is from either softwood or half-hardened cuttings, taken during the summer. 6 to 9 inch hardwood cuttings taken during early autumn or during March root easily.

* photos of unknown internet source

* photo taken on April 11 2010 @ U.S. National Arboretum

* photo taken on Sep 27 2013 in Laurel, MD

* video found on Youtube

'Albiflorus' ( White Rosemary )
Reaches up to 6 x 6 feet or more with white flowers.
Hardy to 0 F.

'Alcalde Cold Hardy'
Sold by High Country Gardens, developed by agronomist Charles Martin, this may be the hardiest of all Rosemary. It forms an upright shrub, reaching up to 4 x 4 feet. The thick foliage is olive-green. The flowers are bright blue. Hardy zones 6 to 10.

Reaches up to 4 x 10 feet in 8 years, reaching a maximum height of 5 feet though easily kept much smaller with pruning. It is very similar in appearance to regular Rosmarinus offinalis.
It is the hardiest of all Rosemary.
Tolerates as low as -10 F and has even been known to survive as low as -19 F protected from wind being planted next to a foundation.

* photos taken on Dec 5 2011 in Columbia, MD

* photo taken on June 23 2013 @ U.S. National Arboretum, DC

* photos taken on Oct 17 2013 in Olney, MD

* photo taken on Aug 13 2017 in Columbia, MD

* photo taken on Nov 5 2017 in Columbia, MD

'Athens Blue Spires'
An upright, vigorous form that is reliably hardy a full zone colder to zone 7 a or even zone 6 on protected sites. Absolutely covered in light blue flowers in early spring.

Foliage has yellow specks.

'Benenden Blue'
Very narrow, deep green leaves and showy intense bright blue flowers. Reaches a maximum size of 4 x 5 feet, though is generally low growing and not exceeding 3 feet in height.

Very vigorous and upright in habit. The aromatic foliage is deep blue-green and the flowers are pale blue.

A large, vigorous shrub reaching up to 8 x 6 feet. Some records include: 4 years - 4.3 feet.
The broad foliage contrasts well with the large, light blue flowers.

'Hill Hardy'
Fast growing and semi-upright in habit, reaching up to 5 x 5 feet.
The dense foliage is deep green.
The lightly-fragrant flowers are bright blue.
Hardier than most Rosemary, north to zone 6, tolerating - 10 F.

'Huntingdon Carpet'
A fast growing, low growing, dense, spreading groundcover form, reaching a maximum size of 2 x 6 feet.
The flowers are bright blue.

* photo taken on June 19 2016 in Elkridge, MD

A trailing form, reaching up to 2 x 8 + feet, making an excellent ground cover. It is mounding and spreads vigorously up to 3 feet or more per year. It can also hang over a wall by as much as 10 feet. 'Irene' is more vigorous than similar looking 'Prostratus'. It has deeper blue flowers in summer and is hardier than most ( zone 7 to 10 ).

'Jessup's Upright'
Vigorous and erect in habit, reaching up to 6 feet in height.

'Joyce de Baggio'
Compact and lower growing.

'Madeline Hill'
Very cold hardy, tolerating as low as -15 F.
Upright in habit, the foliage is deep green and the flowers are pale blue.

'Majorca Pink'
Flowers are lilac-pink; otherwise identical to species.

'Miss Jessopp's Upright'
Vigorous, tall and erect in habit, reaching a maximum size of 7 x 7 feet. Some records include: 5 years - 3 x 2.8 feet.
The foliage is gray-green and the flowers are bright blue.

'Prostratus' ( Cascade Rosemary )
Low, dense, mat forming shrub, reaching up to 2 x 8 feet ( record is 3 x 10 feet ), making it an excellent groundcover or even a hanging basket plant. It is also excellent for use trailing over a dry stone wall.
The foliage is luxuriant green, and the entire plant is covered in showy lavender-blue flowers in summer.
Hardy north to zone 8.

* excellent video found on Youtube!

Pink flowers

'Tuscan Blue'
Fast growing and erect in habit, reaching a maximum size of 10 x 6 ( rarely over 5 ) feet.
The large aromatic foliage is deep green and the flowers are rich clear blue.

* photo taken @ U.S. Botanical Garden, Wash., DC on Aug 25 2014

* excellent video found on Youtube!

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