The annual Fennel is an annual plant native to northern Africa, widespread in the wild also in central and southern Europe and in Asia; it produces ample patches of ground covering, consisting of thin stems, lignified at the base, well branched, which bear broad pinnate leaves, finely incised, which are very reminiscent of the foliage of wild fennel, light green, greyish white on the underside. From spring until autumn, at the apex of the stems large umbrella-shaped inflorescences develop, consisting of small, light green buds that bloom in five-petalled white flowers. The foliage has an intense scent when wrinkled, and even the flowers give off a very particular scent. This plant has been used as a medicinal plant for millennia; it is also used as a flowering plant, in the borders of annuals and flowerbeds, where it becomes a ground cover, reaching a height of 50-80 cm; tends to self-seed easily, it is therefore advisable to check its growth over the years, to prevent it from becoming a pest. The sap has photosensitizing power, it is therefore advisable to handle the flowers and the whole plant with gloves, or to wash the skin that comes into contact with this liquid well.
Ammi visnaga is a species of plant that prefers well-sunny positions, but can tolerate even the slightest shadow; it does not fear frost, especially if it is light and for short periods, even if the young plants tend to produce more flowers than the examples of the previous year, it is therefore often cultivated as an annual.
Ammi can easily withstand periods of prolonged drought, but for better flowering it is advisable to water regularly, when the soil has been dry for several days. They do not require particular fertilizing, but to prolong the flowering it is good to remove the withered floral stems. Beware of water stagnation: before irrigating the plant, check that the soil is dry. Excessive irrigation would cause the plant to rot.
Annual fennel plants are preferably cultivated in clayey soil, quite well drained; they also tend to settle for poor and stony soils.
The reproduction of Ammi visnaga takes place by seed; It is possible to prepare the young plants in February-March, keeping the seed beds in a temperate place, or to sow them directly in April-May, when the minimum temperature is above 10-12 ° C.
Annual fennel - Ammi visnaga: Pests and diseases
Annual fennel plants fear the attack of aphids. These are small insects, better known as "plant lice" that affect most ornamental plants causing depletion of the plant. The aphids in fact suck the sap present inside the fennel plants and cause the deformation of the leaves. In addition to this, they transmit to our seedlings viruses and leave sugary secretions on the plants which consequently cause the possible development of the fumaggine.
The flowers of Ammi visnaga attract pollinating insects, such as bees, wasps and butterflies, so it is advisable to avoid planting the plants too close to the houses.