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Adam’s needle yucca (Yucca filamentosa) is a plant in the agave family that is native to the Southeastern United States. It was an important plant to Native Americans who used its fibers for cord and cloth, and the roots as a shampoo.
Today, the plant is used primarily as an ornamental in the garden. Continue reading for more Adam’s needle information, as well as tips on growing Adam’s needle yucca plants.
Adam’s needle plants are hardy in zones 4-10. They grow 3-4 feet (.91-1.2 m.) tall and wide. The common name Adam’s needle is derived from the plant’s long, sword-like foliage with sharp needle-like tips. These straps of foliage bear tiny thread-like filaments around their edges, which appear as if the plant is peeling.
In late spring, Adam’s needle yucca forms tall stalks from which 2-inch (5 cm.), bell shaped, white flowers hang. Because of these unique lantern-like flower stalks, Adam’s needle yucca is often used in the landscape as a specimen plant. The flowers last for several weeks.
The yucca flowers are only pollinated by the yucca moth. In a mutually beneficial relationship, the female yucca moth visits yucca flowers at night and collects pollen in specialized parts of her mouth. Once she has collected the necessary pollen, she lays her eggs near the ovary of the yucca flower then covers the eggs with the pollen she has collected, thereby fertilizing the plants egg. In this symbiotic relationship, the yucca gets pollinated and the yucca moth caterpillars use the yucca flowers as a host plant.
The Adams Needle plant, also known as Yucca Filamentosa, is a stunning architectural plant that can make a dramatic statement in any garden. With its sword-shaped blue-green leaves and towering flower stalks, this native North American succulent immediately draws the eye. However, in order to keep your Adams Needle looking its best, you need to plant it in the ideal soil.
So what type of soil does the Adams Needle plant prefer? Here’s a complete guide to choosing the perfect soil to help your Yucca Filamentosa thrive
The Adams Needle Plant’s Soil Requirements
In its native habitat in the southeastern United States, the Adams Needle plant grows in sandy soils that drain quickly. This desert-adapted plant does not tolerate sitting in wet, boggy soil Good drainage is absolutely crucial to prevent root rot and other deadly fungal diseases.
The sandy soils where Adams Needle grows naturally tend to be acidic to slightly alkaline, with a pH between 6.0-7.5. The plant does best in soil with a neutral pH around 7.0. Adams Needle tolerates poor, nutrient-deficient soils in the wild. In fact, rich garden soils with high fertility often cause this tough plant to grow too fast and flop over.
When choosing an ideal potting mix or garden soil for Adams Needle keep these requirements in mind
- Exceptional drainage
- pH between 6.0-7.5
- Low to moderate fertility
Avoid Soils That Hold Moisture
The number one cause of failure when growing Adams Needle is planting it in soil that doesn’t drain well. Heavy clay soils, pure peat-based potting mixes, and any soils that stay soggy after watering are sure to rot the roots of this desert plant.
Watch out for bagged “cactus mixes” that contain a high percentage of peat. Peat holds onto moisture and compacts down over time. Opt for cactus mixes with more perlite, sand, or gravel instead. A blend made for succulents and cacti is ideal.
If your garden has dense, clay-based soil, you have two options for growing Adams Needle. The first is to build a raised planting bed and fill it with fast-draining soil. Use a mix of 1/3 native soil, 1/3 coarse sand or gravel, and 1/3 compost.
Your other option is to heavily amend the native clay soil with organic matter like compost to lighten the texture. You’ll also need to add perlite and sand to improve drainage. Thoroughly mix in up to 50% amendments to a depth of at least 12 inches.
Choose a Soilless Mix for Containers
When growing Adams Needle in pots, use a commercial bagged potting soil instead of garden soil. A soilless mix formulated for cacti and succulents is perfect, as it’s lightweight, fast-draining, and low in nutrients.
Avoid potting soils made for African violets or orchids, as these retain too much moisture. Look for key words like “gritty,” “porous,” or “well-drained” on the bag. The mix should contain perlite, sand, gravel, or vermiculite.
You can also make your own custom blend. Mix equal parts potting soil, perlite or gravel, and coconut coir or compost. Adding 1/4 part horticultural charcoal can help remove excess salts.
Use terra cotta pots for Adams Needle, as these porous containers promote evaporation. Make sure pots have drainage holes to prevent waterlogging.
Adjust Soil pH If Needed
Test your soil’s pH before planting Adams Needle. Aim for a neutral pH around 7.0. To lower pH in alkaline soils, amend with elemental sulfur or cottonseed meal.
To raise pH in acidic soils, amend with dolomitic lime or crushed oyster shells. Recheck the pH after 4-6 weeks and reapply amendments if needed until you reach an ideal range.
Go Easy on Fertilizer
Adams Needle prefers infertile soil and can easily suffer fertilizer burn. Use a balanced organic fertilizer in moderation, such as a 5-5-5 or 10-10-10 blend applied at half strength. Fertilize very lightly once in early spring, and use no more than 1/2 teaspoon per square foot of garden space.
When growing in containers, choose a potting mix with little or no fertilizer added. You can apply a diluted liquid fertilizer every 3-4 months through the growing season if plants show signs of nutrient deficiency.
Excess fertilizer causes succulent leaves to grow too fast, taking away energy from flowering. Overfed Adams Needles also become lanky and prone to falling over. Keep them growing slow and steady for best results.
Provide Excellent Drainage
No matter what soil mix you choose, ensuring adequate drainage for Adams Needle is non-negotiable. Here are some tips:
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For in-ground plants, loosen and amend soil to a 12” depth before planting. Break up compacted layers that block water flow.
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Raise the planting bed to improve subsurface drainage.
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Use terra cotta pots or pots with extra drainage holes. Add gravel, styrofoam, etc. at the bottom of pots below the soil level to promote drainage.
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Top off pots and garden beds with an extra inch of gritty material like pea gravel or crushed granite. This creates air chambers to facilitate drainage.
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Avoid saucers under potted Adams Needle, as trapped water will cause root rot.
With its striking form and blooms, Adams Needle Yucca is a sensational plant for both gardens and containers. Paying close attention to its soil drainage needs will ensure your success with this easy-care succulent. Choosing the perfect soil provides just the right conditions for your Adams Needle to thrive for years to come.
How to Grow an Adam’s Needle Yucca Plant
Yucca plants grow best in full sun and dry sites. While they are very tolerant of drought, sandy or compacted soil and salt spray, Adam’s needle yucca cannot tolerate wet or continually damp soils. The roots will rot in cool climates where they are exposed to extremely cold, wet springs.
When planting, be sure to allow at least two to three feet (.61-.91 m.) of space between your yucca and any other plants. Create a hole two times larger and deeper than the root ball, which should be planted level with the ground. Give it a deep watering.
Plant Selection – Adams Needle Yucca
FAQ
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