Agapanthus in pots require regular and appropriate care: watering, fertilising, and pruning are essential actions to ensure their beautiful and long-lasting graphic flowering. However, after a few years, they can become cramped and start to languish. Symptoms include: flowers becoming smaller and stems shorter, yellowing foliage that regenerates more slowly, a hollowing out of the centre of the rootstock, and more frequent watering becoming less effective... Once the diagnosis is made, it's time for surgery! With a knife and some elbow grease, in just 10 minutes, your agapanthus will be revitalised for another four years. When and how should you divide your agapanthus? We’ll tell you everything.
Agapanthus 'Pitchoune Blue', a compact variety suitable for pot cultivation (photo credit: Sapho)
Division should be done at the end of winter
Whether your agapanthus is deciduous or evergreen, it should be divided at the end of winter or the beginning of spring (ideally from March to April). The temperatures are still cool, the days are short, and the growth of evergreen agapanthus is slowed down, making it the optimal time to intervene. You might say, "it also works at the end of summer, from mid-August to early October when the plant is no longer producing flower stems!" That’s true, but the rootstock will need to heal during autumn and winter, when its vegetative activity is at its lowest, and that’s not ideal.
Carefully remove the plant and clean the roots
First, remove the plant from its pot. If the rootstock is very old and roots are protruding from the top of the pot, cut as many roots as possible that are coming out of the bottom of the pot, turn it upside down, and tap it several times to release the root ball. Be careful with terracotta pots, as they are more fragile than plastic pots and roots adhere more easily to the porous wall, so proceed with care. You can slide a long knife blade between the root ball and the pot to detach the roots from the wall. Once the rootstock is extracted, untangle as many roots as possible by hand. Cut away any old black roots and scrape off the old compost.
Cut at the heart and slice into 2, 3, 4...
Equip yourself with a long knife (ideally a bread knife) whose blade has been cleaned and disinfected beforehand. Then, cut into 2, 3, 4, 5... But be careful, if you want a plant that will flower again this year, divide the rootstock into 2 to avoid any stress. If, on the other hand, you want to replant in several pots, in the garden, and share with your neighbour, you can divide it into as many pieces as possible. As long as you cut and keep a piece of rootstock with a root, a rhizome, and a bud, you can produce enough to replant throughout the neighbourhood.
Repot immediately and water generously
Once the rootstock is cut in two, apply wood ash to promote healing and prevent rot. Then repot it immediately in the same pot, adding rich compost mixed with some slow-release fertiliser. Water generously and store your agapanthus in a cool, well-lit room. New leaves will quickly develop, followed later in the season by flower stems.
If you have divided a lot, repot the fragments of rootstock in a pot or a cell, cut the roots in half, and also trim the foliage of the evergreen varieties by half. Water and then closely monitor daily watering during hot weather. Your "babies" can be replanted after 5 to 7 weeks.
What not to do!
If, like me, you had the great foresight to plant your agapanthus in a beautiful bulbous pot... then don’t even try to remove it: it’s impossible! The mass of roots formed prevents the plant from coming out. What to do? Break that beautiful pot or sacrifice the plant? That’s more akin to butchery than division, but the best option is to slice the plant into small pieces to extract it from its pot. The lesson to be learned? Don’t plant directly in a bulbous pot, but in a straight horticultural pot, inserted into a bulbous pot!
Comments