Arrola Chrysanthemum Seeds

Arrola Chrysanthemum is grown for its generous, daisy-form flowers that open as summer fades into autumn, turning the late-season garden into a sheet of warm colour. As a short-day plant, it saves its best show for the shortening days of late summer and autumn, with bloom naturally falling from September to November. Cheerful and dependable in beds, borders and patio pots, it sown from seed in late winter will reach flowering the same year, and a little pinching turns each plant into a rounded, branching mound smothered in blooms, an ornamental that earns its place wherever you want autumn colour.

Planting

Start seed indoors from late winter to mid-spring, roughly 6 to 10 weeks before the last spring frost. Scatter the seed on the surface of the starting mix and only barely press it in, never burying it, because chrysanthemum seed needs light to germinate. Give it bright light throughout germination. At a soil temperature of 18 to 21 C with bottom heat, seedlings appear in about 10 to 14 days; sowing at around 15 C will still germinate within roughly two weeks. Transplant outdoors once the danger of frost has passed, setting plants at the same depth they grew at, never burying the root ball, which would starve the roots of air and invite root rot. Space them about 30 to 45 cm apart, leaving the wider end of that range, around 45 cm, for spreading varieties. Choose a spot in full sun with at least 6 hours of direct light a day, since plants in low light grow weak and spindly with few flowers. Keep them away from street or porch lights at night, as artificial light after dark disrupts the short-day trigger that brings them into bloom.

Fertilizing

Before planting in spring, work a low-nitrogen balanced fertilizer into the bed, about 0.2 kg per square metre of a 5-10-5 blend dug in to roughly 15 cm deep. As plants grow, feed several times with a dilute fertilizer before the buds set, and on poor soils a second, lighter feed of something like 5-10-5 or 10-6-4 around the start of August gives them a boost. Keep nitrogen moderate: it has the biggest effect on growth and flowering, but too much delays bloom and reduces the number of flowers. Once flowering begins, container plants do best switched to a high-potassium feed such as a tomato feed.

Care

Keep the soil evenly moist all through the growing season but never waterlogged. Chrysanthemums are shallow-rooted, so they need frequent watering in hot, dry spells, and good drainage is essential to avoid root rot; for pots, water once the top few centimetres of mix have dried out. To build a bushy, flower-laden plant, pinch the tips to force branching: take the first pinch when plants are about 15 to 20 cm tall, removing roughly 2.5 cm from each shoot tip, then repeat each time the new branches reach about 15 cm. Stop pinching about three months before you want bloom, continuing no later than mid-summer; left un-pinched, plants grow tall, leggy and flower poorly. Watch for aphids, leaf miners, leafhoppers, spider mites (worst in hot, dry weather), caterpillars, capsid bugs, earwigs, and slugs and snails; aphids and leafhoppers also spread viruses, so keeping them in check matters. Avoid overcrowding, deep shade and wet foliage to head off diseases such as white rust, powdery mildew (favoured by cool, humid autumn nights), grey mould, Septoria leaf spot and viral problems. Flower buds form naturally as the days shorten in late summer and autumn, about three months after the last pinch, bringing the display through autumn.