Best place in garden to plant Chrysanthemums
Chrysanthemums like light, sunshine and a well-drained soil. Keep them away from overhanging trees, sheds, fences and the shade of your house. Sunshine encourages strong stems, healthy leaves and brightly coloured blooms. Find a spot with some protection from strong winds. One thing to keep in mind is that wherever you put them, even in the herbaceous border, chrysanthemums will need staking.
Soil Preparation for Chrysanthemums
Choose the place for growing chrysanthemum in the autumn, so that the ground can be prepared for spring planting. Dig it deeply in the autumn. Chop in some well-rotted organic matter and, on heavy land, add some coarse grit or sharp sand to open up the soil so that air will get in and it will drain well. Light, sandy soil will need leaf mould, manure or coarse peat worked in to enrich it, and hold moisture. Chop up manure or leaf mould as you add it, because thick mats of organic matter can slow drainage. Chrysanthemums thrive on an acid soil, although they can tolerate some lime. They grow best at a pH of between 5.8 and 6.5. Soil, on the pH scale, is neutral at 7, below that it is acid, above alkaline. Chrysanthemums planted in soils with a very high or a very low pH will have leaf mottling, discoloured patches and poor growth and blooms.
Best way to plant chrysanthemum plants
You should always firm down chrysanthemums when planting. Firming them into the soil will get the roots quickly into contact with the damp, surrounding earth. Young chrysanthemums need their roots in the shallow upper surface of the ground where a good oxygen supply will help early growth. Firming helps to prevent them being uprooted by spring winds despite the shallow anchorage. Don’t use the handle of your trowel to press down the soil, though; this can damage the young roots. Use your hands and fingers, leaving a small depression around the stem. Water in the plants immediately, but then leave them for three or four days before you water again.
Feeding chrysanthemum plants
Even after digging in plenty of manure and compost in autumn in the border where you plan to put chrysanthemums, you need to feed them later to get good blooms or sprays for indoor displays, or flowers for exhibiting. Chrysanthemums are strong-growing plants with sturdy stems, lots of leaf and big showy flower heads so they have a large appetite for nutrients in the soil.
Digging in organic material in autumn gives the plants a good start in the spring. By early summer though – even if you added fertiliser over winter – the soil and the plants will need a boost. Use for this purpose a good compound fertiliser containing all three of the major plant nutrients – nitrogen, phosphorus and potassium – and traces of iron and magnesium.
Generally, it is wise to have more potassium than nitrogen (too much nitrogen can lead to lush growth at the expense of blooms). Rose or tomato fertilisers, most of which have this balance built in, are ideal.
Sprinkle the fertiliser onto the soil, following the manufacturer’s instructions about dosage. Don’t be tempted to give your plants a touch more than the recommended dose. The rule for feeding chrysanthemums, as all other plants, is – little and often. Apply another feed after 2 weeks and again later after 2 weeks.
Don’t apply granular fertiliser if the ground is dry, it can scorch the root hairs. But you can use liquid fertilisers during dry weather. With these, you can feed the plants as often as needed. Stop feeding when the flower buds show their first signs of colour, but keep on watering regularly.
Staking chrysanthemum plants
When you first plant out in garden or pot, use 15 in split canes. Tie each plant to a cane with one or two plastic or wire rings. Place the 15 in cane in the pot or soil before planting because this prevents damage to young roots. You will be potting up the pot-grown ones, so you can change to a larger stake as you move into the bigger containers.
In the garden you will need a 4-5ft stake by midsummer. By carefully removing the small cane, you can ease your new, larger stake into the same hole, so minimising any damage to the roots.
It is also possible to use a plastic net with a 4-5in mesh to support a whole bed of chrysanthemums. It needs to be staked at the corners and along the sides. Drop the net gently over the young plants, and raise it with them as they grow. In an exposed area, two layers of net may be needed. Use great care when you move the net, or the mesh may strip leaves from the stems.
End of Season care
Cut as soon as flowering has ended, trimming back the main stems to 8-12in. This will let air and light around the base of the plant and encourage the new growth which will give you some small blooms for late cut flowers indoors. It will also keep away damp, and that will lessen the dangers from slugs and mildew.
Wait until the sap has stopped rising to cut back farther and lift the stools. Damp is generally a bigger danger than frost, although frost will damage some varieties if you are late bringing them in.