The Adam’s needle is extremely undemanding. It grows easily on all well-drained soils and shows its magnificent inflorescences in midsummer. Here you will find all the important information about the perennial.
Profile of Adam’s needle:
Scientific name: Yucca filamentosa
Plant family: asparagus family (Asparagaceae)
Other names: common yucca, Spanish bayonet, bear-grass, needle-palm, silk-grass, spoon-leaf yucca
Sowing time: Spring
Planting time: April to August
Flowering period: July to September
Soil quality: stony to loamy, calcipholous, nutrient rich
These information are for temperate climate!
Use in: flower beds, single position, heather garden, prairie garden, rock garden, pot garden
Winter hardiness: hardy, USDA Plant Hardiness Zones: 4-10
Bee and insect friendly: Yes
Plant characteristics and classification of Adam’s needle
Plant order, origin and occurrence of Adam’s needle
The Adam’s needle (Yucca filamentosa) from North America is also called common yucca and is one of the agave plants. It belongs to the asparagus family, in which it is represented with about 40 different species. Their exotic appearance makes them a striking appearance, especially during the flowering period in summer, when the often more than man-sized flower stems open their white, fragrant bell-shape flowers.
Characteristics of Adam’s needle
The yucca grows upright and forms dense cluster with creeping fleshy rhizomes. The stemless gray-green leaves with long, tapered leaves reach heights of up to 80 centimeters (32 in).
From June, the long, 150 to 200 centimeter (5 ft to 6 ft 5 in) high flower stems grow upwards, on which large panicles with whitish bell flowers unfold in midsummer. Flowering continues until August or even September. However, it takes two to three years in the garden for the perennials to start blooming after planting. The Adam’s needle is wintergreen and therefore also present in the cold season.
Adam’s needle – cultivation and care
The Adam’s needle needs a warm and very bright location where it can be quietly exposed to the blazing sun. Even if the heat builds up, this is an advantage for the common yucca. A planting spot to the south, which lies in front of a wall or a house wall, is therefore optimal. Such protection is in any case appropriate in order to keep excessively strong and cold wind away from the heat-loving plant. Apart from the fulfillment of these conditions, care should also be taken to ensure that there is sufficient space. With a diameter of up to one meter (40 in), the plant is not exactly one of the tiny ones and therefore requires a lot of space.
With the substrate for the Adam’s needle, less is more. The plant prefers barren soils that are well-drained and dry. A loamy clay soil based on humus, mixed with plenty of sand and gravel, is a suitable combination. Stony and chalky corners in the garden anyway, where barely anything wants to thrive, are also ideal for the Yucca Filamentosa.
The following are important:
- loose soil conditions
- moderate nutrient content
- no tendency to waterlogging or compression
- good drainage
- pH neutral to basic, can be achieved by liming if necessary
The driest substrate is of little use if the groundwater is very high or the location is right next to a body of water. In addition to the conditions of the soil, attention must also be paid to the conditions at the location.
The plant can be easily grown in large containers. Here the requirements for the substrate are similar to those in the garden. If you don’t want to bother to mix conventional potting soil with peat, sand and light clay, you should use rhododendron soil. This material meets all the needs of the Yucca.
Choosing the right location is essential. Once the plant has established itself and settled in, transplanting is almost impossible. Palm lilies are sensitive to excavation. This can be seen by root division, where a small mistake can lead to the death of the entire plant. A later transplanting of the perennial should only be done in an emergency.
- the planting hole should be about three times the width and depth of the root ball
- the surrounding soil is loosened up with a digging fork
- if necessary, mix the substrate with peat, sand, humus and clay
- insert the plant up to the upper roots
- fill in cavities with the excavated earth
- water vigorously and keep it sufficiently moist
The common yucca can be planted at any time from April to August. In autumn, it makes sense to cover young and freshly planted plants with a thick layer of humus. The Adam’s needle is considered hardy, but young plants cannot protect themselves from freezing temperatures and frost.
Cultivation in a bucket
Planting in a container has several advantages. On the one hand, you can easily move the perennial to another location if necessary. If you don’t have a garden, you can take care of the yucca on the balcony or in the winter garden. Container plants are slightly more demanding than the ones in the bed.
- the substrate must not dry out
- it is advisable to add liquid fertilizer
- the perennials need protection in winter
The requirements for the substrate and the location remain the same. Rhododendron and azalea soil has proven itself. The bucket should be stable and big. Because the roots of the plant exert a strong pressure on the vessel. A too narrow plant tray can inhibit the growth of the perennial.
The result: the common yucca does not bloom. If possible, you should buy a thick clay pot from the garden center. At the bottom of the pot, a drainage made of porous material ensures that excess irrigation and rainwater can drain off quickly. Lava chippings, pebbles and potsherds have proven their worth.
The Adam’s needle is hardy and can withstand short-term dryness without damage. Older plants manage almost without water in summer. Only when the leaves hang limply the plant should be watered immediately.
With the right technique, you can promote flower formation:
- as soon as the top layer of substrate has dried, water
- use calcareous water
- avoid waterlogging
- water in winter
Regular watering is important for young plants. The root ball should not dry out here. In the first months of life, the North American plants are not yet able to absorb the valuable moisture from deeper layers of the earth. The same principle applies to palm lilies in the bucket. Check the substrate regularly and add water in time.
Common yucca is one of the light feeding plants. These plants need a minimum of nutrients and should never be over-fertilized.
- add complete fertilizer before flowering
- do not fertilize during and after flowering
- humus and horn shavings have proven their worth
The plant prepares itself for the cold season shortly after it has faded. Nutrients in any form can significantly weaken the plant at this stage. Alternatively, you can water with pond water or diluted plant swill (e.g. nettle). This contains the minerals necessary for the growth and resistance of the plants. With plants in the bucket, it is sufficient to repot them regularly.
The sharp-edged and pointed leaves of the yucca are evergreen. They form leaf rosettes and can reach a length of over 60 cm (24 in). Even in winter, the perennial may not shed its leaves, so a clearing or topiary is unnecessary.
In certain situations, it still makes sense to use scissors:
- Remove withered flower stems close to the ground
- Cut dead leaves
- Remove leaves with a strong parasite infestation
The Adam’s needle is poisonous and very defensive. For this reason, it makes sense to wear protective clothing, glasses and gloves when cutting. After work, thoroughly clean the adhering plant sap from the tools.
Spoon-leaf yucca (one of the trivial names in English) is an extremely defensive plant. Touching the hard, pointed leaves is painful. At the same time, the consumption is not recommended, all parts of the plant are poisonous. Despite these negative aspects, the Adam’s needle is an extremely distinctive perennial. With its distinctive growth form, the plant enhances dreary areas in the garden. You can buy the solitary plants in a well-stocked garden shop or you can easily multiply existing plants.
Sowing seeds does not work reliably in some latitudes. To successfully pollinate the bell-shaped flowers, a special type of moth is required, which is only available in North America. This problem could be solved by manual pollination by humans. However, there are other, more successful methods of propagating the plant.
Root division and cuttings have proven their worth in everyday gardening. The roots are divided in spring. With this type of propagation, you should proceed carefully so as not to irreparably damage the plant. Especially when digging out, the area and depth should be chosen generously so that as much root mass as possible is preserved.
- dig up the mother plant
- divide the plant into evenly sized pieces
- remove injured roots
- replant the parts
- water vigorously
Use a sharp ax or a solid spade for the division. Despite the massive force, few roots and leaves should be crushed or torn off. It is not uncommon for the plant pieces to take a long time to regenerate. The removal of the “side shoots” is uncomplicated. These are cut off in spring with a spade and placed in a sandy substrate. The soil must not dry out, fertilization is superfluous in the first weeks after replanting.
Diseases and pests
Yuccas are robust. The plant usually forgives maintenance mistakes quickly, but serious shortcomings can prevent the perennial from blooming. Here it is advisable to take a closer look at the location and the substrate. A mistake that can lead to the death of the yucca is overwatering or a heavily compacted soil.
The agave plant does not tolerate waterlogging and moisture, and the moisture also favors the infestation of sac fungi. These pathogens settle on the roots and slowly decompose them. Fungicides and home remedies do not work against root rot. The only countermeasure: Immediately transfer the plant to new substrate. In many cases, the affected plants recover.
Burning spots on the leaves can be a sign of leaf spot disease. The infestation with fungi is promoted by damp weather and wet leaves. The disease is persistent and cannot be combated by chemical means.
- take good care of the Adam’s needle
- pay attention to a sunny location
- the minimum distance to other plants must be observed
- cut the infected leaves completely and dispose of them with household waste
In the case of large-scale infestation, it is advisable to remove the affected plants completely. This measure prevents the spread of the fungal pathogen.
Scale insects are one of the few harmful insects that can be dangerous for common yucca. The cell sap sucking animals are difficult to remove due to their hard shell and can develop an inheritable resistance to insecticides in a short time.
- Collect the scale insects by hand
- Spray and pour nettle slurry
- dab the insects with curd soap mixture or tobacco stock
- Use predators (ladybug, scorpion wasps, hoverflies, green lacewing, predatory beetles such as Rhyzobius)
The fight is long, but should be carried out consistently. This will prevent the plant from suffering further damage and the insects from spreading in the garden.
Sub-zero temperatures can hardly affect older plants in the garden. The perennials have no objection to a warming layer of brushwood or bark mulch. The organic material slowly decomposes and releases nutrients to the soil during this process. In this way, freshly planted yuccas are also prepared for winter. The high humidity can affect the plants. It is recommended to tie them together in autumn.
Container plants need protection in the form of a special fleece. This is wrapped around the pot and prevents the substrate from freezing. The pot should be taken away from the ground and placed on some wood.
Use in the garden
The Adam’s needle is an impressive specimen plant that fits wonderfully in prairie gardens and gravel beds. They can also be cultivated in vessels. The flowers are popular with bees and butterflies. As a planting partner there are for example pearly everlasting (Anaphalis triplinervis ‘summer rain’), elephant’s ears (Bergenia), baby’s breath (Gypsophila), lavender, stonecrop (Sedum) or lamb’s ear (Stachys byzantina).
The commercially available varieties are almost exclusively hybrid plants. These vary in height and flower color. The following are some of the most popular varieties.
Yucca filamentosa ‘polar bear’
- This Adam’s needle is characterized by cream-white flowers and a stature height of almost 100 cm (40 in)
Yucca filamentosa ‘Bright Edge’
- with the green-yellow striped leaves and pink flowers, this variety is an eye-catcher in the garden
Yucca filamentosa ‘bell bush’
- this yucca captivates with its blue-green foliage and white-pink flowers
- can reach a maximum height of approx. 200 cm (80 in)
Yucca filamentosa ‘snow spruce’
- white flowers and strong, upright growing leaves characterize this variety