Calylophus serrulatus Superlophus Yellow - Yellow Sundrops

Calylophus serrulatus 'Superlophus Yellow' (synonym Oenothera serrulata 'Superlophus Yellow') is a remarkably floriferous perennial bush that blooms in summer, with large lemon yellow flowers that open during the day, unlike those of its close relative, the evening primrose. It forms a slightly loose, low bushy clump, with slender, long, bright green leaves. It is a plant that thrives in full sun and well-drained, even dry soil. Perfectly suited for rock gardens, borders, and waterless flower beds, it is also welcomed in containers to liven up the terrace or balcony throughout the summer.

Oenothera serrulata 'Superlophus Yellow' is a selection by Voltz known for its wider flowers compared to the species. The wild species is native to dry meadows and mesas in western North America, particularly the Great Plains from Canada to Texas. In well-drained, dry (rocky) soil, its roots can withstand temperatures as low as -15°C. It belongs to the Onagraceae family. The 'Superlophus Yellow' variety is a woody-based perennial with a taproot that can reach deep for moisture. The root does not like to be disturbed. The plant forms a low, slightly loose clump, with few branches, measuring between 25 and 45cm in height. It has narrow, lance-shaped leaves with distinct toothed edges, a fairly light green color, and can reach up to 5-6cm in length. This deciduous foliage dries up in autumn. The flowering period extends from June-July to September, even in dry soil. The cup-shaped flowers have 4 lemon yellow petals, measuring 3 to 4cm in diameter, and bloom during the day. This flowering attracts bees and butterflies. The flowers give way to 2cm long seed capsules.

This Calylophus 'Superlophus Yellow' is a plant that thrives in full sun and well-drained, even dry soil. It will be the perfect companion for rock gardens, slopes, and border plantings, especially in Mediterranean regions. When grown in pots or containers on a terrace or balcony, it will require more regular watering. Pairing it with blue-flowering shrubby salvias will create a beautiful effect. It will also be a great companion for lavenders and Echinops or globe thistles. It can also be planted in front of shrubs such as Perovskia, Teucrium 'Azureum', and Caryopteris.