Another gardening project on the schedule for fall’s cool days is the division of long-standing clumps of Agapanthus.
The genus Agapanthus includes six to 10 species, all of which are native to South Africa. The common name, “Lily of the Nile,” is misleading, since the River Nile is in Africa’s northern region. The plant is widely grown in the world, and there are numerous varieties, including natural selections and hybrid cultivars.
When I moved to my current home four decades ago, the garden included a large section of Agapanthus, which had been spreading for many years. I saw the clump as more a problem than an asset. A friend volunteered to uproot the clump with his Bobcat (an adult toy). The burdensome work was finished in a short time, leaving only the hauling task.
At the time, I regarded the Agapanthus as a common plant, almost weed-like. In fact, this is a desirable addition for the garden, providing good height, excellent foliage and blossoms, and easy care. I eventually appreciated the plant.
This Agapanthus grows evergreen and well in the Bay Area’s Mediterranean climate. There are some dwarf hybrids, e.g. “Tinkerbell,” but most varieties develop luxurious green foliage in clumps 2-to-3 feet tall and wide, with flower spikes rising 3-to-4 feet high, producing attractive displays. The long bloom period ranges from June to October, depending on the variety.
Agapanthus plants grow readily in well-drained soil and full sun. Once established, they are strong growers, requiring little irrigation or care, although annual mulching with well-aged compost will support healthy development and generous blooming.
Clumps of this plant become larger each year and should be divided every four-to-six years to avoid congestion (reduced blooms). They can be replanted as a swath or separate features in the garden, or shared with other gardeners.
There are three Agapanthus varieties growing closely together within my South African perennial bed, providing interesting blossom 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 finished blooming in October, we cut the flower stalks low. We could have left the seed heads on display and as bird food.
We then decided to divide the clumps, which had been in the ground for more than six years. That’s a good practice to be done in Autumn, but the challenge now is to keep the varieties separate. It can be difficult to identify plants with similar forms when they are out of bloom.
This experience justifies photographic documentation of the garden, even when the plant names are known and perhaps even noted on a garden map or plant list. That’s another resolution for the new year.
Dividing Agapanthus clumps begins by lifting the clumps, which can be large and heavy. This can be done best by trenching around the clump, pushing a flat spade under the clump, and lifting at several locations around the clump. Then, roll the clump out of the bed and onto a flat area.
The plant grows from rhizomes, which are mostly underground, serving as storage organs. Thick, white, fleshy roots grow out of the rhizomes.
Once the clump is out of the ground, the rhizomes and roots can be divided with a sharp spade, taking care that each section has at least two growing points. With larger clumps, dividing can be easiest using two garden forks back-to-back.
Dividing is the hard part; replanting is relatively easy, as long space is available with full sun exposure and well-drained soil. If my new swath of plants has randomly mixed blossom colors, that could be a feature rather than a bug.
Hopefully, we will have more seasonal rains during the next few months; regular watering in the spring would help the plants to establish.
Tom Karwin is past president of Friends of the UC Santa Cruz Arboretum and the Monterey Bay Iris Society.
