Can I cut down my peonies now? What about daylilies?
They're looking kind of worn and so are other things. I would have
liked to cut them down when it was nicer outside but I was told
it's too early, that cutting them then would make them grow back
and waste energy.
One more thing. We have a shredder and plan to shred the
leaves from the trees and also shred the garden stuff. Anything we
should know?- J.H. -
Cut away. Shred it up!
By Halloween we've been cutting back perennials for over two
months, since late summer nights turned from hot to cool. We cut
whenever we didn't like a plant's looks anymore or when we saw
discoloration indicating disease. For instance, we clipped peonies
down to the ground that have purple-brown splotches or streaks on
the leaves or stems. It spread out the garden clean up and is the
simplest way to stay ahead of fungal diseases that develop on peony
buds and leaves. Those fungi would have worked their way to the
root but we didn't give them enough time.
(This is not a fall-only tactic. We cut ruthlessly all season in pursuit of
good looks and good health. For instance, we mow down daylilies all
through the season, whenever they look shabby!)
Right: Daylilies in our care may wonder what they've done to
deserve such rough treatment. We razed this bunch in late July when
they looked shabby. Here they are October 2, grown back and looking
lush.
Seven minutes later they're razed again. Before the season
truly ends in late November's freezes, these plants will grow again
and be a few inches high. They won't be hurt by the effort.
Meanwhile, we taken them out of the way as we cut and
edge.
We cut to eliminate things that are in the way. Also, if
something isn't contributing to a composition, it's probably
detracting. Cut it out of the garden like you'd crop it out of the
photograph.
Cut to learn wait-ers from growers
Fall garden clean up is about equal parts science and art, best
learned by doing. Cut, and watch! You won't kill anything by
cutting but in the doing you will learn how the various plants
behave and look. For instance:
- Some perennials won't grow new foliage after being cut, no
matter when the cut comes. Peonies cut in late summer wait until
the next spring to grow back. They need a winter-long cold period,
then a resumption of warmth. Only then do the buds on the roots
sprout. A number of perennials follow this routine, including
bleeding heart and gayfeather (Liatris).
- On the other end of the spectrum are ever-growing perennials
like daylilies, bee balm (Monarda) and daisies. They
develop new leaves all the time unless it's winter-cold. Each leaf
produces energy all the while it's in the sun and the plant socks
that away as starch in growth buds. The plants are so prolific that
they always end up ahead over a season, with more buds ready to go
in spring than were there a year ago. This is the case even when
the first or last leaves of the season are killed by freeze while
so young that they haven't yet produced enough energy to replace
themselves.
Below, right: Bee balm (Monarda didyma) is always growing
new from its base. No matter when you cut it back, this
plant will say, "Hey, I wasn't done yet!" Yet there's no harm done
if you cut it when you will. 
Be like Nature, cut when you will!
By the time tree leaves begin to fall, some perennials have been
touched by frost or browned out. Gardeners have no qualm about
cutting them.
Others remain green. It's those that give people pause.
The thing to keep in mind is that in fall, what's green today
can be blackened by frost tonight. Ma Nature doesn't ask a plant's
permission and the abrupt end doesn't hinder regrowth in spring or
during a long fall. Follow Nature's lead: Cut whenever you choose
to cut rather than waiting for some sign from the plant.
Any new foliage that appears after a cut is not a problem, not a
waste, and doesn't affect our reasons for cutting in the first
place -- to remove potential trouble and also clear the field so we
can see better to weed and divide.
Bonus: To shred what you cut
That's great to have a shredder. Using fall leaves as mulch
saves on yard waste bags and recycles in place the nutrients a tree
used in leaf production. It also reduces the amount of mulch we
buy-- which cuts down on weed seeds and other undesirables that can
come in with imported material. The leaves don't have to be
shredded to be used as mulch, but many people prefer that look.
Debris from seriously troubled plants: Off to a hot
compost
So, shred away. Just try to keep diseased stuff out of the mix,
by sending anything suspicious to a hot compost. (Yard waste
collected by garbage companies goes to a hot compost.) The heat of
a compost kills bacteria, fungi and insects or insect eggs.
Things we consider suspicious: Leaves and stems that discolored
and dropped off prematurely, or those from plants that were very
poor performers -- puny or malformed. Plant problems have very
descriptive names, such as powdery mildew, scab, rust, tar
spot, blotch, leaf miner and leaf skeletonizer. We watch now for
the telltale marks left by these insects and diseases. (Look at
those names and each problem's appearance in Key
Words Unlock Problems.)
Don't over-think this or be too worried about it. You'll know
bad when you see it. If it's just a few bad leaves or stems here
and there, that's normal and should not cause you great
concern.
Above: We've learned to watch for spots, streaks, aborted
flower buds and discolored stem bases on peony. More on this fungus
called Peony Botrytis in issue
#116, issue
#88 and Grow 572.
Below: You'll know trouble when you see it. Let's say all
the other hostas you cut and weed around in fall still had leaves
attached (A), with good sized buds formed and forming (B), and then
you came across a hosta with no leaves, almost no visible bud (C)
and many remnants of decayed stem bases (D). You'd know that second
hosta was in trouble. Best move: Just get rid of it. (More on Hosta crown rot through University Extension
bulletins.)
In fact, allowing a little of the bad to remain is a way of
helping plants keep fighting their own battles so we can stay out
of the mix. Most plants do cross paths with their pests but also
carry their own solutions in the form of beneficial fungi and eggs
of predatory insects. So the odd stem and leaf that shows just a
little damage is almost certainly hosting the solution as well as
the pest. Both will overwinter and trouble will probably remain in
check. The trouble we clip and take away is whatever we see that
was extensive, an indication that plant couldn't control the
problem on its own.
Download a step-by-step
Our steps in garden clean up are listed in The Art of Fall
Garden Clean up,
downloadable here.
Hands-on
For hands-on learning, check our calendar in fall for
our Garden by Janet & Steven hands-on free sessions.
Come cut with us!