Sweet William
A vigorous African marigold with orange flowers, as useful as it is beautiful.
About the variety. The single flowers are precious for bees and the plant acts as a natural repellent against nematodes, parasites that attack roots and can kill neighbouring crops. Grows up to 70–90 cm.
Itinerário técnico
Um guia de cultivo passo a passo, da sementeira à colheita.
Sow direct where it is to flower, half a centimetre to one centimetre deep, or in trays for transplanting at four or five weeks. Germination takes seven to fifteen days. Sow after the last frosts, once the soil is warm, for summer flowering: an autumn sowing in the open dies at the first frost. Thin without hesitation once the plants have four true leaves, to the spacing given: crowded plants give weak stems and few flowers.
It adapts to ordinary free draining soils at a pH between 6.0 and 7.5. Over rich soil is counter productive: it gives tall leafy plants with few flowers, and that is the commonest mistake in flower beds. If the soil is heavy, work in coarse sand or compost to improve drainage, because standing water in winter rots the roots.
It wants full sun, at least six hours a day, and temperatures between 15 °C and 25 °C. With less sun the plants go leggy and flower poorly. Frost ends the cycle. On the Portuguese coast and in southern Spain it takes the heat well and flowers right through the summer. Inland in Iberia water more through the dry months. In France and Germany the natural season is spring and summer, sowing once the soil has warmed steadily. In Italy the same rule applies as in the rest of the Mediterranean: spring and autumn in the centre and south, spring and summer in the north. At the height of summer flowering slows and the flowers come smaller: light shade over midday and regular watering keep the plant going.
It needs very little. Ordinary soil with some mature compost is enough, and excess nitrogen is counter productive because it gives plenty of leaf and few flowers. To push flowering, apply a potassium rich feed when the first buds appear.
Water regularly during establishment and moderately after that, letting the surface dry between waterings. Water at the base in the morning, because wet flowers rot and damp foliage brings powdery mildew.
Hoe often and always shallowly, because the roots are short, near the surface and break easily. The best method is to prepare the bed two or three weeks in advance, let the first flush of weeds germinate, remove it and only then sow: that gives you a decisive head start. A thin layer of sieved compost between the rows greatly reduces later work.
Aphids gather on flower buds and soft tips and are the commonest pest: apply potassium soap and encourage ladybirds and hoverflies, which do most of the work. Slugs and snails destroy seedlings: protect with an ash barrier in the first weeks. Thrips and red spider mite appear in dry heat. Avoid spraying during flowering, so you do not harm pollinators.
Powdery mildew covers the leaves with white bloom at the end of summer and is nearly unavoidable on crowded plants: space well and apply potassium bicarbonate at the first signs. Botrytis rots the flowers in damp weather and damping off kills seedlings in waterlogged sowings. Remove faded flowers and diseased leaves regularly.
Cut the flowers early in the morning, as they are opening but not yet fully open, and put them straight into water. Deadhead regularly: as long as no seed forms, the plant keeps flowering, and that is the one rule that really matters for extending the display. Leave a few flowers to set seed at the end of the season if you want natural self-sowing. Allow about 90 to 100 days from transplanting to the first harvest of this variety. The reference colour is orange, and that is what tells you it is ready.
