Tree
Peonies Grow Successfully in Minnesota
by Harvey Buchite growing plants in Zone 4 on well drained sandy soil.
I can’t
believe I waited so many years before trying to grow tree peonies because I
believed what I read in so many of the books and articles written for northern
gardeners. Contrary to what I read they are hardy, long lived beautiful
flowering shrubs. They come from
mountain habitats often with cold winters and drier summers. They always are found in areas of good
drainage mostly among other shrubs.
When I
saw a rather large bush with exotic looking leaves in the garden of my
gardening friend Jean I could see that the tree peony was more than a few years
old. In fact I believe she said it was
more than 25 years old and that it had dark red flowers.
That’s
when I began to plant tree peonies!
First an un-named pink got me started.
It turned out to be Hana Kisoi one of the easiest to grow and bloom with
great big large pink flowers. But the
flowers are only a part of the joy you get from your tree peonies. The spring foliage is exotic with the edges
of the leaves outlined in precise red to contrast with pale to dark green
leaves. The buds are often speckled
with rose dots as they begin to expand to an up-side-down top shape.
At
first I covered them carefully in the fall for winter protection and found out
later that the protection was not necessary except to keep hungry rabbits from
eating the stems in the winter. Later I
added a white, Renkaku, then a red, Hoki, then a yellow, High Noon, and then a
maroon, Shima Daijin, and then ... some new ones from China and even some tree
peony species that I grew from seed including P. lutea and P.
suffruticosa.
Soil
preparation always pays off for me on the sandy soil that I have to garden
in. I begin by adding compost or peat
moss and always try to prepare a hole bigger than the roots of the plant. The next important thing is to plant the
tree peony DEEP! As deep as 3-4 inches
below the grafted portion with at least two of the eyes on the stem just below
the soil.
Your
most important factor in success of growing tree peonies is to get them off the
herbaceous nurse root and onto their own roots. To do that you have to plant them deep.
Once
planted they should be given a nice wood chip mulch to conserve moisture and
the soil should be kept evenly moist.
The first year I see little growth.
But the second year when the tree peony is making its own roots the
plant will double and triple in size to 3-4 feet across so give them room. One
common mistake of new tree peony growers is to cut the plant back in the
fall. Not only is this not necessary
but you are cutting off next years flower buds!
As far
as a site to grow I have seen them growing very well on the east side of a
house and in dappled shade. When a wood
mulch is used I have even grown them in full sun. On my sandy soil I have had leaf scorch but the plants bloomed
well and put on better growth than the plants I have in shade that are
competing with neighboring tree roots.
While
quite winter hardy tree peonies do begin growth very early in the spring and
once growth has started they are subject to frost damage like any actively
growing plant.
The
solution is easy, cover the plants with a light weight blanket over night until
the temperatures are above freezing.
Remove it during the day if it is to be above freezing to allow the
plant to continue healthy growth.
This
habit of beginning early spring growth can be modified by planting in a shadier
protected spot that actually slows early spring growth. The north side of a building is sometimes
recommended
for this
reason.
Some
books mention them preferring a slightly alkaline soil, but I have not seen
much difference growing them in a slightly acidic soil.
Yellow
varieties; like High Noon and the pink variety Hana Kisoi seem to be the
fastest growing, most white varieties
like Godaishu and Renkaku are vigorous too while the red flowered varieties and
purple flowered varieties are less so,
although
they make fine plants in time.
I have
noticed a greater number of Chinese Tree
Peonies
showing up listed for sale and would welcome any comments from our membership
on their growth.
We have 12 varieties planted out for trial at
the nursery and some at home.
Those
planted at home really suffered as our family was away for a month during the
hot dry part of the summer. So the
lesson is to make sure you have back up waterers when you are away for
vacation, or don’t blame the plants for failing.
I am
becoming more interested in these most beautiful early blooming members of our
peony family and have started seed from the semi-double pinks, reds and purples
for planting out in our woodland display in the future.
Give
tree peonies a try I think you will like what you see.