Yucca Carnerosana Data Sheet

• Common names: Giant Spanish Dagger

• Latin name: Yucca Carnerosana

• Genus: Yucca

• Height: 6 m (20 ft)

• Type: Evergreen

• Hardiness: Zone 5

• Conservation status: Endangered

Yucca Carnerosana is often referred to as the Giant Spanish dagger yucca. The leaves are impressive and thick with a dark green colour. The leaves form a rosette and reach 100 cm in length, with a width of 8 cm. This yucca flowers once every 4 years or so, producing a flower stem up to 2 m tall. The flowers are white with slight cream highlights. The flower stem grows in an upright position and can weigh 35 Kg when in full bloom. This species has a massive thick trunk that can reach 12" in diameter.

This yucca is native to Texas in the United States and is very frost hardy. the plant should be kept as dry as possible during severe freezes.

Pre Germination

These seeds need no pretreatment as such. Germination time can be reduced by soaking the black seeds in water for 24 hours to soften the hard shell prior to sowing. Once soaked, fill trays or pots with quality compost and firm down gently. Spread seeds across the surface; around 10 in a 10 cm pot is ideal. Cover with 3 mm of compost and gently firm down.

Compost should be kept damp, not soaking wet or dried out. A temperature of between 60F and 70F is perfect for yucca germination. Place pots or trays on a cool to warm windowsill or in a cool conservatory. Germination should occur at 1–3 weeks, depending on the soaking process, germination can take up to 8 weeks.

Post Germination

Keep seedlings in a bright, well-ventilated area to reduce the risk of damping off disease; a windowsill is ideal. Ensure they don't dry out or become waterlogged. These seedlings will quickly develop a large root system. They can be separated into 4" pots at 15–20 weeks; by this stage they are frost hardy and can stay outside all year. Fertilization is not required up to this point. During spring and summer we advise using an NPK 10-10-10 fertilizer every 4 weeks.