Taxonomy and Botany of Adam's Needle
Adam's needle is the common name for a plant known as Yucca filamentosa in plant taxonomy.
Yucca filamentosa is a broadleaf evergreen shrub. It is related to many of the other commonly grown cacti and succulents. The family to which it belongs reveals another relative: It is in the asparagus family.
What Adam's Needle Looks Like
Adam's needle grows to a height of about 2-3 feet (not counting the flower stalk) when it matures, with a spread slightly less than that.
The leaves are blade-like (beginners may feel that the shape somewhat looks like that of bearded iris, although long-time gardeners will scoff at the comparison) and form a basal rosette. The slender leaves can reach a length of over 2 feet on large plants, and they end in a spine. Curled threads line the edges of the leaves, giving it its species name (filamentosa, meaning a thread or "filament").
The flower stalk that grows up from the center of the foliage in late spring can double the size of this yucca plant over time (sometimes growing to 8 feet tall or more). The flower cluster usually appears (in a zone-5 landscape) right around the beginning of summer. The individual blooms take the shape of nodding, white bells.
How long does it take a new Yucca filamentosa to bloom for the first time? It is common to have to wait about three years for one to bloom for the first time.
Growing Zones, Sun and Soil Needs
Although native to the Southeastern U.S., this hardy succulent has naturalized farther north.
You can plant Yucca filamentosa in growing zones 5-10.
Adam's needle needs a well-drained soil. Keep the soil a bit on the dry side. It does not need a fertile soil, so it is a good choice for an area that has poor soil. It does not seem to mind pollutants, either, making it a good choice for roadside plantings.
You can grow it in full sun (under which conditions it will thrive best), but the plant will tolerate a little shade.
Care, Other Types of Yucca Plants
This succulent is one of the easiest plants to grow outdoors. Very little care is needed for it. So if landscape maintenance is not your cup of tea, Yucca filamentosa could be an ideal plant for you. The ones that you perhaps grew up with decades ago on your parents' property and that have been left alone all these years look, no doubt, none the worse for wear. At most (if you are very fussy about the way you keep up your yard), you might want to cut off the spent flower stalks at the end of the year and, once in a while, remove old leaves that have turned brown.
There are many other types of yucca plants besides Yucca filamentosa. To name just a few:
- Soap-tree yucca (Yucca elata) is a tree form that can reach 15 feet tall. It can be grown in zones 5-8.
- Do not confuse #1 with Yucca glauca, sometimes called "soapweed." This plant is suitable for zones 3-10.
- Yucca flaccida derives its species name from the fact that its leaves stand fairly limp (those on most yucca plants are rigid). Grow it in zones 4-10.
Those of you familiar with the American Southwest will not be surprised to hear that there are tree-form yuccas, because another is the well-known Joshua tree (Yucca brevifolia), found in such places as the Mojave Desert.
There is a bicolored type of Adam's needle, too, named Yucca filamentosa 'Bright Edge.' Even brighter are the types with gold in their leaves, such as:
- 'Golden Sword'
- ‘Garland’s Gold’
Does It Have Something to Do With Cassava?
No. Cassava (Manihot esculenta) is a root vegetable used in Latin food. It is sometimes referred to by such names as "manioc," "manioc root" or (and here is the source of confusion) "yuca" or "yuca root." Note that there is only one C in the spelling. M. esculenta is not related to yucca plants.
Does Adam's Needle Attract Wildlife?
These yucca plants attract butterflies. Gardeners who detest "creepy-crawlies" will not like the fact that they also draw earwigs. On the bright side, these pests are unlikely to do any serious damage to your Adam's needle.
The calling card for Adam's needle may well be, first and foremost, that it is a tough plant.
Proof of how tough it is are the following traits (two that are soil-related and two that are pest-related):
In terms of soil, Adam's needle is:
Pests, meanwhile, give it little trouble, since it is:
Uses in Landscaping
The potential uses for this yucca plant in your yard are many, based both on how it looks and on how tough it is. Let's begin with uses suggested by how it looks.
Even though Yucca filamentosa is a native of the Southeastern U.S., it is a great fit in a Southwestern theme, since it looks like it belongs in a desert. You can also make use of the fine texture of its leaves by growing it next to plants that have foliage of a coarser texture, thereby creating contrast.
Meanwhile, its well-known toughness makes Adam's needle a good fit in dry regions or problem areas of the landscape that seem too dry for most plants. Consider it as an option for xeriscaping, a form of sustainable landscaping. Yucca is also a great choice when growing a rock garden. Or grow it on a slope that has always been a problem for you, to provide soil erosion control.