You can read here where the unusual name of the false dragonhead comes from, how you can master the beautiful but proliferating perennial in the garden and what else is important when planting and caring for.
Profile of false dragonhead:
Scientific name: Physostegia virginiana
Plant family: mint family (Lamiaceae)
Other names: obedient plant
Sowing time: spring
Planting time: spring to autumn
Flowering period: July to September
Location: sunny to partially shaded
Soil quality: sandy to loamy, moderately nutritious, humus rich
These information are for temperate climate!
Use in: flower beds, bouquets, group planting, planters, borders, flower garden, natural garden, potted garden, water garden
Winter hardiness: hardy, USDA Plant Hardiness Zones: 4 (-34 °C / -25 °F)
Bee and insect friendly: Yes
Plant characteristics and classification of false dragonhead
Plant order, origin and occurrence of false dragonhead
The false dragonhead (Physostegia virginiana) belongs to the mint family (Lamiaceae) and a plant within the genus of lionshearts (Physostegia). It is native to eastern and central North America. The tall and vigorous perennial with the attractive flowers is an asset to the garden, if you know how to keep them under control.
Characteristics of false dragonhead
The frost hardy false dragonhead is very vigorous and spreads strongly by underground runners. Many clumps quickly form in the garden. The square stems of the false dragonhead can grow up to 120 centimeters (48 in) high. The bushy perennial reaches between 60 and 90 centimeters )24 and 36 in) in width.
On the stems of Physostegia sit crossed, oppositely, lanceolate, dark green serrated leaves which are up to 12.5 cm long (5 in).
The pink to red-violet flowers of the false dragonhead explain the unusual name of the plant: they end up in, up to 25 centimeters (10 in) long, slender and dense spikes, which refer to the dragonheads of the related dragonhead (Dracocephalum), a genus to which the plant once belonged. The flowering period lasts from the end of July until September.
After flowering, candle-shaped seed heads with small nuts develop.
False dragonhead – cultivation and care
In any case, Physostegia needs a sheltered place in the garden. It can be both full sun and partially shaded. The less light the perennial gets, the fewer flowers it forms and the weaker the stems.
Basically, the false dragonhead copes well with any well-drained garden soil. The ideal soil is moderately rich in nutrients and humus rich, which is fresh to moist and sandy-loamy. Physostegia tolerates pH values from slightly acidic to slightly alkaline.
The false dragonhead can be planted from spring to autumn. There are 8 to 11 plants per square meter (10 sq ft.) at a distance of 30 centimeters (12 in). If you want to prevent excessive spreading from the beginning, put a rhizome barrier in the ground.
The false dragonhead requires regular watering during the summer months so that the root ball does not dry out. Water the plant continuously during long droughts. Regular mulching has proven to be a useful maintenance measure. The layer protects the substrate from excessive evaporation. Thanks to its good water storage capacity, a mulch cover prevents waterlogging.
It is best to supply the false dragonhead with compost in early spring, because this promotes its growth and abundance of flowers. A further application of fertilizer is only necessary when needed.
A complete pruning back of the perennial should be carried out every year in autumn so that it can sprout again fresh in spring.
Since the false dragonhead is not very stable, but grows tall, the stems often have to be supported with a stick. After flowering, Physostegia is cut back close to the ground, which prevents it from self-sowing and promotes growth in the next year. Pure green leaves grow again and again on variegated varieties. They should be removed to keep the pretty foliage.
Articular flowers are divided every two years and dense stands are thus cleared. The division takes place in autumn after the flowering period. Use a digging fork to lift it out the root ball of the ground. The roots should not be injured so that the partial plants can grow well after the measure.
Separate the rhizome into several pieces. Each root part should have a distinctive fine root system and several leaves. Recut unclean cuts and remove injured plant parts. Put the new plants immediately in the prepared planting holes and water the substrate thoroughly.
The seeds of the false dragonheads that are sown in early spring need cold to germ. Lower temperatures between 5 and 10 °C (41 and 50 °F) are optimal for germination.
You can spread the seeds directly in the bed or sprinkle them in a freezer bag with some damp sand. The bag is stored in the refrigerator for two to four weeks. After stratification, the seeds are sown on a nutrient-poor potting compost or in the bed. Keep the soil evenly moist.
Articular flowers can be propagated via head cuttings. Cut shoots 10 to 15 centimeters (4 to 6 in) long directly below a bud. Remove the bottom leaves and put the shoots in the soil. The cuttings need a high level of humidity to form roots. You can pull a plastic film over the jar or wet the substrate with the shoots daily with water. As soon as the shoots have developed new leaves, they can be repotted.
Diseases and pests
Sometimes blight, a fungal disease, affects the articular flower. Rust can also occur.
False dragonheads prove to be frost hardy down to -34 °C / -25 °F. Additional winter protection is required in rough locations or during snow-free winter months. Cover the ground with fir branches or brushwood. When layering, make sure that the branches are close together. Spruce twigs have proven to be effective. The branches shed their needles in spring so that the plants get more light again.
When the plants grow under evergreen woods such as rhododendron, conifers or cherry laurel, the foliage serves as a natural protection against the cold. False dragonheads are also better protected in winter on growth sites directly on the south wall of a house.
This is how to protect container plants:
- Place the pot on an insulating surface, like a wooden block
- Wrap several layers of fabric or fleece around the bucket
- Moisten the substrate on frost-free days
Use in the garden
As a valuable nectar and pollen plant, the false dragonhead should not be missing in any natural garden: especially bumblebees, wild bees and butterflies love it. Hobby gardeners appreciate them for their high growth and magnificent flowers. Planted in small groups, it beautifies beds and borders, but can also be kept in a pot on a balcony or terrace. Good planting partners are other magnificent perennials such as crimson beebalm or New England aster. Physostegia also thrives very well in moist soil near the pond. It is also an excellent cut flower for the vase.
The numerous varieties of false dragonheads differ in stature height, but above all in flower color and foliage. A selection:
- ‘Vivid’: lower (50 to 60 cm / 20 to 24 in), more compact and more stable than the species, pink flowers
- ‘Summer Snow’: large white flowers, 70 to 80 centimeters (28 to 32 in) high, excellent cut flowers
- ‘Olympus Gold’: leaves with golden yellow edges, pale pink flowers
- ‘Bouquet Rose’: violet-pink flowers, 80 to 90 centimeters (32 to 36 in) high, blooms earlier than the species
- ‘Miss Manners’: branches more strongly than the species, pure white flowers
- ‘Variegata’: gray-green / white variegated leaves, pale pink flowers
- ‘Crystal Peak White’: white flowers, attracting butterflies in droves