Adam's needle (Yucca filamentosa) is a slow-growing broadleaf evergreen shrub that is often used in Southwest-themed landscapes. Adam's needle is related to many other commonly grown cacti and succulents; it's a yucca plant in the asparagus family. Adam's needle is a virtually stemless shrub that looks more like a perennial plant. The blade-like leaves form a basal rosette ending in spines. The foliage clumps are usually 2 to 3 feet tall, with curled threads lining the edges of the leaves, giving it its species name—filamentosa—for its threads or "filaments."
Mature plants about 4 or 5 years old will send up flower stalks from the center of the foliage in late spring, which can double the height of this yucca plant, sometimes growing to over 8 feet tall. The blooms look like nodding, white bells. Adam's needle can be planted almost any time, though it is most commonly available at nurseries in the spring. However, transplanting, or taking basal offsets of Y. filamentosa is best done in the fall.
|Botanical Name||Yucca filamentosa|
|Common Names||Adam's needle, needle palm, Spanish bayonet|
|Plant Type||Broadleaf evergreen shrub|
|Mature Size||4 to 8 feet tall, 2- to 3-foot spread|
|Sun Exposure||Full sun|
|Soil Type||Dry to medium-moisture, well-drained soil|
|Soil pH||5.5 to 7.5 (acidic to slightly alkaline)|
|Bloom Time||June to July|
|Flower Color||Creamy white|
|Hardiness Zones||5 to 10 (USDA)|
|Native Area||Sandy beaches and fields of Southeastern U.S.|
|Toxicity||Toxic to cats, dogs, and horses; sap may cause human skin irritation|
Adam's Needle Care
This succulent is one of the easiest plants to grow outdoors. It needs very little care, so if landscape maintenance is not your cup of tea, Yucca filamentosa could be an ideal plant for you. The only thing usually required—and only if you're fussy about the look of your landscape—is to cut off the spent flower stalks at the end of the year and occasionally remove old leaves that have turned brown.
Though this is a slow-growing plant, it's best to give it 2 to 3 feet of space around the plant, which will make it easy to work around the spiky leaves. Create a planting hole about twice as deep and wide as the nursery container, and plant the specimen at the same level as it grows in the container.
Yucca filamentosa has virtually no severe disease or pest issues. Adam's needle attracts butterflies but also draws earwigs; these pests are unlikely to do any serious damage to the plants.
This plant grows best in full sun but will tolerate a little shade.
Adam's needle needs well-drained soil, and you should keep it a bit on the dry side. It does not require fertile soil, so it is a good choice for poor, rocky, or sandy soil areas. It also does not seem to mind pollutants or salty soil, making it suitable for roadside plantings. Yucca is a great choice when growing a rock garden, and it works well on a slope to provide valuable soil erosion control.
Adam's needle has good drought tolerance once established, and it is often used in xeriscape landscaping. In its first year, you should water it lightly every week, but after this, it probably will not need supplemental watering at all. However, container-grown plants do need a small amount of weekly water.
Temperature and Humidity
Although native to the southeastern U.S., this hardy succulent has naturalized farther north. You can plant Yucca filamentosa in USDA hardiness zones 5 to 10, where it readily adapts to all climate variations within those zones. This plant usually readily survives temperatures down to 5 F, but it will survive temps of -10 to -20 F if covered with mulch over winter.
Adam's needle usually does fine without any feeding, but if the plant is languishing, feed it once in spring with a granular general-purpose fertilizer mixed into the soil around the base of the plant.
Is Adam's Need Toxic?
According to the American Society for the Prevention of Cruelty to Animals, yucca plants are not poisonous to humans, but they contain saponins that make them toxic to horses, cats, and dogs.
Symptoms of Poisoning
An animal that has ingested the yucca plant may have excessive drooling, vomiting, weakness, incoordination, dilated pupils in cats, depression, and diarrhea. The plant has a very bitter taste, which generally makes it unpalatable to house pets. The plant is more dangerous to grazing animals. It is unlikely a house pet would tolerate eating enough of the yucca to suffer a life-threatening condition.
Adam's Needle Varieties
- 'Bright Edge': Is a good bicolored type of Adam's needle. It is well suited for zones 4 to 9.
- 'Golden Sword': A bright variation with gold in their leaves
- 'Garland’s Gold': Another good, golden, and bright variety
You can trim flower stalks down once the blooms have faded. While wearing sturdy gloves, prune away these leaves down close to the base of the plant.
Propagating Adam's Needle
Mature plants will begin to grow basal offsets around the base of the plant, and these can be easily cut away and replanted to propagate new plants.
Potting and Repotting Adam's Needle
Like other yuccas, Adam's needle can make a good specimen for large containers. Use a porous succulent/cactus potting mix. Adam's needle generally prefers to be alone in its pot, but it blends well with other large potted plants arranged on a patio or deck, or around a sunny entrance.
Winter burn may affect some of the leaves in regions with cold, windy winters. By late summer, start to reduce the amount of water the plant receives. Stop watering entirely by September. Yucca plants will stop storing water in their leaves during dormancy over the winter, protecting the plant from deep freezes.
Let the stalks naturally die back before cutting to allow the plant to store needed nutrients from the roots for next season's growth. Cut the stalks to the ground and apply a 6- to 8-inch layer of mulching material over the plant in late fall before the first frost. Insulate and protect it from the cold winter weather. Place plastic sheeting or burlap over the mulch pile to further insulate. Hold down with stakes or large rocks placed around the edges. Remove the sheeting and mulch in the spring after the chance of frost has passed.
Adam's Needle vs. Other Yucca Plants
There are many other types of yucca plants besides Yucca filamentosa, including:
- Yucca elata (soap-tree yucca): a tree that can reach 15 feet tall. It can be grown in zones 5 to 8
- Yucca glauca (soapweed): Not to be confused with soap-tree yucca, this plant is suitable for zones 3 to 10
- Yucca flaccid: This yucca's leaves stand fairly limp while most other yucca plants have rigid leaves; it grows in zones 4 to 10
- Yucca brevifolia: Also known as the Joshua tree of the American Southwest, it is another type of tree-form yucca suitable for zones 6 to 8