Tough flowering perennials require about the same level of care as neighboring woody
plants. Some additional effort can enhance their impact.
Perennial Care Recommendations
Plucking off spent flowers (dead heading) encourages a longer and more prolific blooming
season. In most commercially maintained landscapes, dead heading is too time consuming,
but cutting off spent flower stalks (at the base) enhances many perennials (with
the exception of Fortnight Lilies).
Most perennials lose vigor as they age. Dividing the root mass (rhizomes, tubers,
etc.) of excessively mature plants during the Winter can turn one struggling clump
of ratty foliage into multiple healthy plants, allowing bare soil areas to be planted
without purchasing nursery stock.
Society Garlic(Tulbaghia violacea) is extremely durable and blooms for about 8 months.
The plants send up too many flower stems to prune them individually, so shearing
them at the edge of the foliage mass is effective and promotes reblooming when the
stalks dry up. Minor shearing damage to the tips of the foliage does not seem to
harm the plants.
Daylilies(Hemerocallis hybrids) provide a wide variety of flower colors, forms and
blooming seasons. Mixing multiple hybrids extends the bloom season and showcases
Most of the hybrids specified by this Office have evergreen foliage which should
not be cut back unless damaged foliage is widespread. Dead foliage usually collects
around the bases of the plants and can be pulled away by hand.
The flower stalks should be cut off within the foliage clump when the plant finishes
blooming. At 3-5 years of age, Daylilies can be divided and used to revegetate bare
New Zealand Flax(Phormium tenax) is generally much larger than the other perennials
addressed on this page and is grown primarily for its foliage. Damaged leaves should
be cut off at the base of the clump rather than cutting off damaged tips. The plants
should never be sheared into “decorative” shapes. When significant dead foliage builds
up, the plant should be cut off 3-4 inches above finish grade in late Winter.
Fortnight Lilies(Dietes bicolor & vegeta) are reliable bloomers with evergreen foliage.
Each flower stem will produce for a year or more and ought to be left in place until
it has clearly dried up. The dead stems should be cut off at their bases.
Some damaged leaves are nearly always present on Fortnight Lilies. Pruning away dead
foliage at the base of the clump gives the plant a tidier look, but it is not necessary.
At about 25°, most or all the leaves will turn brown and not recover. When frost
danger ends, the plants should be cut flat to a height of 3 inches and allowed to
Shearing strap leaved perennials into balls (as shown at right) does not rejuvenate
them. While new growth will struggle through the mutilated foliage, the plant will
not recover for months.
Dead or damaged foliage should be cut off at the base of the clump. If the quantity
of poor quality leaves is excessive, the plant should be cut flat to a height of
2 to 3 inches in late Winter.
Lily-of-the-Nile(Agapanthus orientalis) is probably the most widely used perennial
in Central California. Flower stalks should be cut off within the foliage clump after
the plants finish blooming. Leaves are damaged by frost and become brown goo in severe
freezes. Damaged or dead foliage can be cut off when there is no further danger of
frost. The plants will recover quickly.