The angular Solomon’s seal is one of the wild perennials that enrich not only shady garden spaces. Here you can find out what makes the former plant so attractive.
Profile of angular Solomon’s seal:
Scientific name: Polygonatum odoratum
Plant family: asparagus family (Asparagaceae)
Other names: scented Solomon’s seal
Sowing time: autumn
Planting time: spring
Flowering period: May to June
Location: partially shady
Soil quality: sandy to loamy, moderately nutritious, humus rich
These information are for temperate climate!
Use in: flower beds, ground cover, underplantin,g borders, natural garden, forest garden
Winter hardiness: hardy, USDA Plant Hardiness Zones: 4 (-32 °C / -25 °F)
Bee and insect friendly: Yes
Plant characteristics and classification of angular Solomon’s seal
Plant order, origin and occurrence of angular Solomon’s seal
The angular Solomon’s seal (Polygonatum odoratum) has a similar attractive appearance like the lily of the valley, to which it is closely related. Thus, botany long assigned the perennial to the lily of the valley family (Convallariaceae), but has recently placed it in the asparagus family (Asparagaceae). This almost exotic forest perennial can be found in sparse oak and pine forests or at the edge of sunny bushes. In the past, the plant, also known as scented Solomon’s seal, was a popular medicinal and magic plant. However, caution is still advised when using it in the garden: The plant is poisonous in all parts.
Characteristics of angular Solomon’s seal
The flower stalks hang elegantly arching over and grow 20 to 40 centimeters (8 to 16 in) tall. This gives the angular Solomon’s seal a striking stature that stands out among the largely ground-covering shade perennials.
The fresh green leaves are parallnervous and run to oval. Their consistency is nice and firm, which pays off in the vase as a companion green. In autumn, the foliage of Polygonatum odoratum turns yellow.
From May to June appear white flower bells with a green tip. Strung like beads, one or two flowers hang from each leaf axil. Their fragrance is reminiscent of bitter almonds, which attracts insects. They need a long proboscis to get at the sweet nectar in the tubular flowers. But the scent is so enticing that bumblebees with short proboscises, for example, simply bite a hole in the side of the flower.
Seeds ripen from the flowers and turn blackish blue by autumn. They first form a pretty contrast to the yellow colored leaves and later an ornamental fruit until winter, if they are not eaten by birds before.
Angular Solomon’s seal – cultivation and care
Angular Solomon’s seal, like all species of Polygonatum, feels comfortable on a humus rich, loose forest soil in partially shady. However, the wild species can stand much drier and also sunnier. In the wild, it will escape to rocky sunny sites if competition occurs. Therefore, you can even use the Solomon’s seal in rocky steppe-like plantings and at the sunny edge of a wood.
The soil for Polygonatum odoratum should ideally be dry to fresh, loamy-sandy and humus.
The best time to plant out the plants is in early spring, because then angular Solomon’s seal in the same year decorate the garden with lush flowers. Freshly separated rhizomes are planted in the fall. Angular Solomon’s seal should be planted in the bed according to their growth width. Make sure that the distance between them is at least 20 centimeters (8 in). In order for the plants to develop a dense bushy stand, you can plant 12 plants per square meter (10 sq ft).
Keep the soil evenly moist during the growing season. Short dry periods do not cause problems for adult plants as long as the rhizome is not completely dry. Young plants should be watered more frequently during non-rainy periods so that the substrate is continuously moist. In the spring, you can mulch the soil. This promotes growth and at the same time ensures that the soil does not dry out.
If you mulch or mix compost under the substrate in the spring, no further fertilization is necessary during the year. Plants feed on nutrients throughout the growing season. Overfertilization can weaken the plant and cause disease or promote pest infestation.
Pruning measures are not recommended, as they weaken the angular Solomon’s seal. As deciduous plants, they extract their energy from the above-ground parts of the plant in the fall and store it in the rhizome. Once the leaves are completely withered, they can be cut off close to the ground. This measure is not absolutely necessary. The leaf mass protects the soil during the winter months and is decomposed. This gives the plants fresh nutrients the next spring, which they use for new shoots.
You can divide the fleshy roots of the plant in spring or autumn. To do this, carefully dig up the rhizomes and separate sections from the knotty root pieces. Replace them elsewhere in the garden.
The rhizome-forming plants can be propagated by division and thus be rejuvenated. To do this, dig up a healthy plant in the fall and divide a strong rootstock with a sharp knife. You can look for the nodular thickenings that serve as predetermined breaking points. Often rhizomes can be divided by breaking off a thickening. The section should have as many fine roots as possible so that it can grow more quickly in the new location. The mother plant should also have a sufficient network of fine roots.
The soil at the new location should be well loosened. A digging fork is perfect, as it penetrates to deeper layers of soil. Plant the cutting at the same depth where the mother plant is growing. Press the substrate and water the soil sufficiently so that holes close and the tuber grows better. In the next few years, do not disturb the daughter plant by digging. It takes some time to form new thickening at the root.
Angular Solomon’s seal can also be propagated by seed. The seeds need cold to germinate and therefore need a cold stimulus. This can be done naturally by the onset of winter or artificially.
If you collect fruit in the fall, you should clean the seeds from the flesh and let them dry. Just before winter, sow the seeds directly in the open ground. Choose a partially shady location where the substrate has humus properties. When the snow melts the next year, the seed coat will swell and germination will begin. If you sow the seeds in the spring, germination also occurs after winter the following year.
You can positively influence the germination process by storing the seeds for four weeks in a warm place with temperatures of 20 °C / 68 °F. Sprinkle the seeds in a freezer bag filled with sand and store it in the refrigerator for four to six weeks. Regularly check the moisture of the substrate. This measure serves as stratification.
Then sprinkle the seeds on a potting compost and place the planter in a cool place with temperatures between 0 and 12 °C / 32 and 53 °F. Large temperature jumps should be avoided so as not to interrupt the germination process. As soon as the first leaves appear, the plants are pricked out. In April, the seedlings can be planted in the desired location in the garden.
Diseases and pests
There are no known diseases that cause problems for the angular Solomon’s seal. Droopy hanging leaves or reduced vigor are due to incorrect site conditions or care measures. Control moisture and lime content in the soil.
Many pests spread on plants that are already weakened. You can prevent infestations by spraying plants with garlic or horseradish broth in the spring.
Solomon’s seal sawfly
Angular Solomon’s seal is the host plant of the Solomon’s seal sawfly, whose larvae can heavily feed on the plant’s leaves and flowers in the spring. This wasp species lays its eggs on the plants leaves in May. An infestation is usually not noticed until the larvae have hatched and leave feeding marks in the leaves. They eat the leaves bare from the shoot tip to the leaf base, leaving a skeleton behind. Infested shoot tips should be generously cut off and removed to prevent the larvae from continuing to eat through the leaf mass. You can periodically scan the plant for pests and eggs and strip them from the leaves.
In the spring, slugs become annoying pests that feed on the freshly sprouting plants. They are particularly comfortable in the moist and shady locations where angular Solomon’s seal grows. Within a short time, these pests can eat entire stands bare. Loosen the soil regularly to make it harder for slugs to get in.
Help against slugs:
- Erect snail fences
- alternatively lay out pointed stones as obstacles
- Coffee grounds keep the pests away
- distribute snail nematodes with the watering water
Polygonatum odoratum is winter-hardy and survives temperatures down to -32 °C / -25 °F. This high frost resistance is related to the natural location, because in forests the soil is protected by fallen leaves, so only in particularly severe winter months the top layer of soil freezes through. The root tubers lie at a frost-free depth.
In snowy winter months, a blanket of snow protects the soil of open gardens from freezing. If the snow cover is missing, you should cover the substrate with a thick layer of mulch. Fir branches, brushwood and leaves are suitable for this purpose. Alternatively, you can spread thick straw mats in the bed.
Use in the garden
In shaded areas, the arching foliage perennial adds diversity among evergreens, woodland steinia and other groundcovers, or becomes an undergrowth for woody plants such as hydrangeas. Angular Solomon’s seal achieves one of the most beautiful effects between hostas, ferns and grasses that prefer shade. If its flowering time is to coincide with other spring flowering plants, Siberian bugloss and phloxes (e.g. Phlox divaricata and Phlox stolonifera) are suitable. If you want to stagger the flowering, choose, for example, liverworts and cowslips as a vanguard, and low astilbes as a follower. Or interweave angular Solomon’s seal with long-shoots of bloody crane’s-bill (Geranium sanguineum). Even as a counterpart to hedged garden structures, Polygonatum odoratum is good when generously strung along a spring path.