Crocus

Plant family

Iris family (Iridaceae)

Season Overview

Details

Light requirement

Sunny

Water requirement

Moist

Soil

Medium (loamy)

Nutrient requirement

Medium

Dark germinator

Germination temperature

10 - 15 °C (Degrees Celsius)

Plant distance

10 cm

Row spacing

10 cm

Seeding depth

8 cm

Instructions

Description

The genus Crocus belongs to the iris family (Iridaceae). There are around 90 known species, as well as numerous subspecies and hybrids that have been created by crossing different species. Natural habitats include rocky slopes, evergreen oak scrub and coniferous forests. Crocus chrysanthus, Crocus tommasinianus, Crocus siberi and Crocus vernus play an important role in garden culture. These species are spring bloomers, while the autumn crocus (Crocus speciosus) is a species that blooms in the fall weeks. The Saffron Crocus (Crocus sativus) is also an autumn bloomer - its orange thread-like pistils are harvested, dried and have been traded as saffron for thousands of years. Saffron threads are among the most expensive spices in the world. In addition to cultivation areas in Iran and Afghanistan, saffron is also grown in Spain, France, Italy and Austria. Appearance and growth Crocuses are often mistakenly categorized as bulbous plants. However, they have a so-called stem tuber, which is a thickened stem part that grows underground. This tuber is annual, but every spring one or more new daughter tubers are formed. The old tuber then dies off. The tubers sprout basal narrow leaves that resemble blades of grass. The plants grow between 5 and 15 centimeters tall, depending on the species. Crocuses are divided into spring flowering, large-flowered hybrids and fall flowering. The first group blooms in early spring from February to March, while the large-flowered hybrids occasionally bloom into April. Autumn crocuses usually bloom from September to October. The predominant flower colors are purple, yellow and white, and there are also bicolor varieties. Spring flowering species are important forage plants for bees and bumblebees, which mainly collect the protein and vitamin-rich pollen. Important species and varieties The large genus of crocuses can be divided into three groups: the early flowering botanical crocuses, the large-flowered hybrids (often simply called garden crocuses) and the autumn flowering crocuses. Early flowering botanical crocuses are characterized by more delicate flowers that often appear in late winter. Even a blanket of snow and freezing temperatures do not prevent these crocuses from pushing their buds out of the ground. The group of early flowering crocuses includes the fairy crocus, the spring crocus and the small crocus. There are many varieties available. Orange Monarch', a relatively new variety of the small crocus, is special because the dark orange-yellow color of the flowers is very unusual for crocuses. From March onwards, the larger garden crocuses join the group, with colors ranging from white to yellow to purple, and the 'Pickwick' variety is even striped. In addition to the crocus hybrids, this group also includes the golden crocus, which produces several bright yellow flowers per bulb in March/April. There is now a large selection of large-flowered hybrids, such as 'Haarlem Gem' with light purple flowers, the white-flowered 'Jeanne d'Arc' or 'Queen of the Blues', whose violet-blue flowers have a silvery sheen. Around September, the autumn-flowering crocuses make their grand entrance. There are three main species: the purple-blue gorgeous crocus, the saffron crocus and the ring crocus (Crocus kotschyanus). The 'Albus' (white) and 'Conqueror' (sky blue with dark veins) crocus varieties are popular.

Growing tips

Location and soil Early-flowering botanical crocuses thrive best in sunny spots in the garden, while the autumn-flowering crocuses also do well in semi-shady spots. The large-flowered hybrids, i.e. the classic garden crocuses, prefer a sunny to semi-shady location. However, it is important to know that the longer the location is shaded during the day, the sparser the flowering will be. What they all have in common is their preference for well-drained soil, as waterlogging causes the tubers to rot. While the spring-flowering species also thrive in sandy or stony soils, the autumn crocuses prefer a good garden soil with a clay content. For early bloomers, on the other hand, you should improve heavy soil with a little sand. Planting The best time to plant spring-flowering crocuses is from October to November, while fall-flowering species are best planted in August. The planting depth for spring-flowering crocuses is six to ten centimetres, as is the distance between the bulbs. Autumn-flowering crocuses are planted a little deeper because of the larger bulbs. As crocuses use their traction roots to access nutrients and moisture from deeper soil layers over time, it is not a problem if the tubers are planted relatively shallowly. Always place about ten bulbs next to each other, as the small flowers are best displayed in groups. If you want to turn your lawn into a crocus meadow, a loose, random distribution is recommended. The golden crocus (Crocus flavus), spring crocus, small crocus and elfin crocus are particularly suitable for growing wild. They form dense clumps that should be divided after a few years. Care tips Crocuses do not require any special care once planted. It is important not to cut off the leaves immediately after flowering. They should only be removed when they wilt, otherwise the plants will be weakened and die more quickly. Therefore, if you have planted crocuses in the lawn, you should wait until the leaves have yellowed before cutting them back. If necessary, fertilize in early spring as soon as the leaves sprout. An organic liquid fertilizer that is applied with the irrigation water is suitable.