Smyrnium are erect, branching biennials with broadly oblong, divided lower leaves and rounded upper leaves. In late spring and early summer they produce branched umbels of small, greenish-yellow flowers
Moist and well drained means exactly what it sounds like. Soil is moist without being soggy because the texture of the soil allows excess moisture to drain away. Most plants like about 1 inch of water per week. Amending your soil with compost will help improve texture and water holding or draining capacity. A 3 inch layer of mulch will help to maintain soil moisture and studies have shown that mulched plants grow faster than non-mulched plants.
This spring bloomer produces bright chartreuse floral domes atop bract-like, rounded leaves that are pierced by the flower's stem. This plant's form and color contrast well with spring bulbs. It grows 3 feet tall and 2 feet wide. Let it regenerate itself by self-sowing.
Annuals and perennials may be fertilized using: 1.water-soluble, quick release fertilizers; 2. temperature controlled slow-release fertilizers; or 3. organic fertilizers such as fish emulsion. Water soluble fertilizers are generally used every two weeks during the growing season or per label instructions. Controlled, slow-release fertilizers are worked into the soil ususally only once during the growing season or per label directions. For organic fertilizers such as fish emulsion, follow label directions as they may vary per product.
As perennials establish, it is important to prune them back and thin them out occasionally. This will prevent them from completely taking over an area to the exclusion of other plants, and also will increase air circulation thereby reducing the incidence of diseases like botrytis and powdery mildew.
Not all medicinal, dye or aromatic plants are edible, some are toxic if eaten and others are dangerous if applied to the skin. Smyrnium perfoliatum is a BIENNIAL growing to 1.5 m (5ft) by 0.6 m (2ft in). It is hardy to zone (UK) 6 and is not frost tender. It is in flower from June to August, and the seeds ripen from July to September.