|1||15C+||Indoor||Grow as a houseplant or under heated glass.|
|2||10 to 15C+||Indoor / Outdoor||Grow indoors, or outdoors in summer in a sheltered spot|
|3||5 to 10C||Tender||Grow outdoors in summer, and in a heated glasshouse in winter.|
|4||1 to 5C||Tender||Grow outdoors or under glass without risk of frost.|
|5||-5 to 1C||Half-Hardy||Hardy in coastal/mild/sheltered areas. Will not tolerate hard/sudden frost. May require winter protection in situ. such as fleece or straw mulch.|
|6||-10 to -5C||Hardy||May suffer at altitude, central/northerly locations, harsh winters, cold gardens and when grown in pots.|
|7||-15 to -10C+||Hardy||Will survive most severe winters but may be at risk in central/northerly locations and in pots. Top growth may be destroyed but will usually re-grow.|
|8||-20 to -15C||Hardy||Will survive severe winter, but may need protection when grown in pots.|
|9||-20C & Colder||Very Hardy / Hardy||in the severest European climates.|
Originating from S. USA and N. Mexico
A large ‘Spanish Dagger’ specimen is an arresting sight with its broad and sharply-tipped leaves making a dome shape at the top of the plant. The leaves are a rich olive/mid-green colour with wide brown margins, which come together at the tip of the leaf to form a long and extremely sharp brown spike. Creamy white, thread-like filaments are produced along the margins of the leaves from the brown edges, giving the foliage extra character and decorative interest.
Although the leaves are thick, rigid, and tough, they are not fleshy like other succulents, and are held stiffly in the cron – upright in the top, emerging from a central rosette, and held at descending angles further down the plant. On young plants the dome-shaped basal rosette widens at ground level to become a broad mound shape up to 40cm across before starting to grow upward, creating a dense column of spiky leaves, making a plant 1.5m, possibly 2m wide. As the plant gets taller the lower leaves die back and gradually a woody trunk is formed. The old leaves can persist on the trunk, making a skirt of downward hanging dead foliage and forming a rugged natural-looking specimen, or they can be removed to reveal the wide, impressive trunk in order to maximise the architectural impact of the plant.
Flowers are produced at the growing tip of the plant on a 1.2m tall inflorescence, (branching structure, supporting numerous individual blooms), which is held well above the leaves. The flowers are a greenish-white colour and are reputed to be edible, and apparently eaten with scrambled eggs!
Known to withstand temperatures as low as -18 degrees in desert climates, Yucca carnerosana rates highly amongst all exotic species we can grow in the UK for hardiness and sheer architectural impact. However, its hardiness in dry desert conditions, where extremely low temperatures can be recorded overnight, does not compare to prolonged wet and cold in the UK, so whilst -18 is an impressive figure for this species we rate this as -10 or -12 degrees hardy for UK weather conditions, which is still pretty good for such an impressive looking plant, and makes it a good choice for southern UK, coastal regions and inner city gardens.
Apart from the matter of its hardiness, the Spanish Dagger is a very easy species to grow, being fast, pest free and undemanding of any care, so long as it is given free draining soil and full sun.
Height and spread after 3 – 4 years 1m x 1m
Semi-mature height and spread after 5 – 6 years 1.8m x 1.5m
Potential semi-mature height and spread after 10 – 15 years 3m x 1.8m
Plants in the wild have been known to reach 8.5m tall and be multi-headed