Another garden project on the agenda for those chilly fall days is dividing long-standing agapanthus trees.
The genus Agapanthus includes six to ten species, all native to South Africa. The common name “Lily of the Nile” is misleading as the Nile River is located in the northern region of Africa. The plant is cultivated worldwide and there are numerous varieties including natural selections and hybrid varieties.
A full clump of Agapanthus ‘Getty White’ just starting to bloom.
When I moved into my current home four decades ago, the garden included a large proportion of agapanthus that had been propagating for many years. I saw the lump as a problem rather than an asset. A friend volunteered to help uproot the clump with his bobcat (an adult toy). The tedious work was done in a short time, all that remained was the towing work.
At that time I considered the agapanthus as an ordinary plant, almost like a weed. In fact, this is a desirable addition to the garden, offering good height, excellent foliage and flowers, and easy maintenance. At some point I appreciated the plant.
Evergreen, this agapanthus grows well in the Mediterranean climate of the Bay Area. There are some dwarf hybrids, e.g. B. ‘Tinkerbell’, but most varieties develop lush green foliage in clumps 2 to 3 feet tall and wide, with bud sites reaching 3 to 4 feet tall and producing attractive displays. Depending on the variety, the long flowering period extends from June to October.
Agapanthus plants grow easily in well-drained soil and full sun. Once established, they are vigorous growers requiring little watering or maintenance, although annual mulching with well-aged compost encourages healthy development and bountiful flowering.
Agapanthus ‘Getty White’ in a close-up of the large round white flower cluster.
Clumps of this plant grow larger each year and should be divided every four to six years to avoid congestion (reduced blooms). They can be replanted as swaths or separate features in the garden, or shared with other gardeners.
In my South African perennial border, three agapanthus varieties grow close together and offer interesting flower color comparisons.
A. praecox ssp orientalis ‘Getty White’ (white)
A. orientalis spp. orientalis (unlisted variety)(medium blue)
A. africanus x pendulus ‘Storm Cloud’ (dark blue)
When they have finished flowering in October, we cut the flower stalks low. We could have displayed the seed heads and left them as birdseed.
We then decided to divide the clumps that had been in the ground for more than six years. This is good fall practice, but the challenge now is to keep the varieties separate. It can be difficult to identify plants with similar shapes when they are no longer flowering.
This experience justifies photographic documentation of the garden, even if the plant names are known and perhaps even noted on a garden map or list of plants. This is another New Year’s resolution.
Agapanthus precox
Dividing clumps of agapanthus starts with lifting the clumps, which can be large and heavy. This is best done by digging a ditch around the clump, sliding a flat spade under the clump and lifting in several places around the clump. Then roll the clump out of the bed and onto a flat surface.
The plant grows from mostly underground rhizomes, which serve as storage organs. Thick, white, fleshy roots grow from the rhizomes.
Once the clump is out of the ground, the rhizomes and roots can be divided with a sharp spade, making sure each section has at least two growing points. For larger clumps, dividing may be easiest using two garden forks back-to-back.
Sharing is the hard part; Transplanting is relatively easy given long space with full sun exposure and well-drained soil. If my new plant swarm has randomly mixed flower colors, that could be a trait rather than a bug.
Hopefully we will have more seasonal rains in the next few months; Regular watering in the spring would help the plants become established.
Tom Karwin is past president of Friends of the UC Santa Cruz Arboretum and the Monterey Bay Iris Society.
