These plants that we removed from pots were able to keep almost all of their root system. However a clump dug up from the ground will have lost a lot of the root system. When this happens we cut almost all the foliage off the plant, this will reduce the stress on the plant and allow the root system time to regrow.
I also took an overgrown root-bound agapanthus out of a pot and divided the root ball into 4 quarters with a spade and replanted them. A year later, each quarter section is as big as the original. You can't kill the darn things.
Dig out scattered plants. Dispose of ALL corms and root fragments at a refuse transfer station or dry them out and burn them. Usually follow up with spraying. Slash leaves close to ground & paint fresh stump with picloram gel, or (100ml triclopyr/1L water) or (10g metsulfuron + 20ml penetrant/1L water).
This plant can be easily propagated through division in late autumn to winter by carefully removing it from the ground or the pot. Gently shake off some of the soil so that you can see the roots and the individual plants. Carefully pull the individual plants apart making sure that each one retains its own roots.
Agapanthus are easy to propagate by division to obtain plants identical to the parent plant, this is best done between spring and early summer. Avoid splitting plants too often as this will reduce flowering. Large clumps in the border should be lifted in spring every 4 - 6 years and replanted.
Propagating plants from cuttings is one of the easiest and most used methods of propagation. Many plants will root from just a section of a plant. Some plants will root in water, but cuttings will develop a better root system when rooted in a soil-less potting mix.
Dividing and transplanting agapanthus
However, if left untouched for any length of time, they will become overcrowded and may flower poorly. Lifting and dividing agapanthus every 3 to 4 years will promote better flowering.
“Agapanthus stems can be pruned at ground level when the flower has gone over unless you want to leave them in the garden for winter structure,” says Patrick Fairweather, the Managing Director of Fairweather's Nursery.
Agapanthus plants have the ability to swiftly invade bushland and out compete native species. They are invasive and pose a significant threat to the integrity of our natural bushland.
Because agapanthus plants spread quickly, they are regarded as an invasive weed in parts of New South Wales and Victoria. Your local council can provide guidance on growing agapanthus, which may include dead-heading flowers before seed dispersal.
Without deadheading, the plant goes to seed and the blooming season is shortened considerably. To deadhead agapanthus, simply use pruners or garden shears to remove the faded flower and the stalk at the base of the plant.
Agapanthus plants benefit from regular deadheading, which helps them conserve energy. Simply remove the entire flower stem once the blooms have faded.
Every two to three years, you may need to repot your plants into slightly larger containers because although they like being a bit root bound, they'll appreciate a fresh potting mix and a bit more room to grow. As a rule of thumb, aim to repot into a container that's two inches larger in diameter than the existing pot.
Snip off the spent blooms before they go to seed with sharp and clean secateurs, cutting off the stalks close to the base of the plant to keep things neat. Place the dead flower heads into your composting system.
Ideally you should split and divide your agapanthus every four to six years. Agapanthus can also readily be propagated by seed. If you grow several different named varieties in your garden do not expect the seedlings to come true.
Agapanthus grows and spreads by fleshy rhizomes that act as storage roots. The plant retains nutrients in its roots and may be divided to create more plants. Use a sharp shovel to dig up an established plant and divide it into several sections, each with roots and foliage.
Many plants go dormant during the winter months, (many plants stop growing during the Winter months), and a major procedure such as root pruning, can totally shock their system and eventually kill them.
Roots serve two purposes:
This is called the "root flare." The closer the roots are to the tree, the more important they are for keeping the tree upright. Cutting these roots can lead to instability. These smaller, fibrous roots absorb water and minerals to be transported into the tree.
Don't remove more than 1/3 of anchoring roots.
Avoid removing large, or anchoring, roots. Anchoring roots provide a lot of support and branch off into many smaller roots. If you must remove some, don't remove over 1/3 of all anchoring roots.