Chrysanthemum

Boron deficiency in chrysanthemum and pyrethrum

In mild cases of boron deficiency, the petals fail to unroll properly and become “quilled." When the deficiency is severe, you will see symptoms in the leaves which are brittle and closely spaced. Some down-curling of the leaves may occur and leaf tips may become chlorotic. There may be some loss of flower color. When the boron deficiency is acute, the buds fail to open properly. Growing point death is followed by multiple shoot formation.

Boron deficiency in pyrethrum causes the development of misshapen and malformed flowers and apical dieback in pyrethrum. Ray florets may be reduced to one third their normal length. They have ragged tips and they may be formed on only part of the circumference. In some cases, ray florets may be completely absent.