Tree Peonies

What is it that focuses your attention on the gentle curves of a white flower? Is it the lack of colour that accentuates the shape and the translucence of a white petal? Whatever the reason, there is something magical about the soft lines of a white peony in flower. 

Years ago I saw the most exquisite white Tree Peony at the Royal Botanical Garden in Hamilton and I promised myself that, if I ever saw a similar peony for sale, I would buy it on the spot. 

By chance, I finally came across a single white Tree Peony last week. Fall is actually the best time to buy and plant any type of peony, but I was so taken with this beauty, I decided to overlook the season and the considerable expense (almost $50), and purchase it.

Fresh growth on my Tree Peony is carried on stems that are a soft magenta color.

Newly emerging green foliage is edged with a deep rose colour.

I have lots of experience growing herbaceous peonies, but none with Tree Peonies. Some research was therefore in order. I gave my peony a drink and left it on a garden bench in the sun, while I went inside to look up some basic facts.

I grabbed a coffee and sat down to read the plant tag as the first order of business. The first words on the label were a warning:

Before you plant

If you don't have a chance to plant your peony immediately after you purchase it, make sure it is in a lightly shaded spot out of the sun's direct rays while it waits to find a home in your garden. Don't allow it to dry out. Keep the soil in the pot moist.

Oops! I ran out to rescue my peony from the sunny bench where I had left it.

Tree Peonies are actually a woody shrub. 

They come in colours beyond white: pink, red, coral, purple, yellow and blends of different colours. Tree Peonies grow slowly. It may take 5-10 years for them to reach their mature size.

Choosing a Site

Peonies of all types dislike being moved. Choosing the right spot for my new peony, therefore, required some careful consideration. Too much sun and the flower petals might fade. Too much shade and the peony would have weak, slow growth. Peonies also like some protection from the wind. 

And on top of all that, you need to keep in mind that a Tree Peony will require lots of room to grow. They can reach 4-7 feet in height and 4-5 feet wide! An ideal spot would be a sheltered location with morning sun and a little bit of dappled shade during the hottest hours of the day. 

Hmm....in what area of my garden was there morning sun and light afternoon shade?

When best to plant a Tree Peony

The best time to plant any type of Peony is in the fall, but nurseries, like the one where I bought mine, often sell them in the spring.

Planting Preparations

Planting depths vary depending on the root type. Grafted tree peonies should be planted so that the graft is four to six inches below the soil. Tree peonies grown on their own roots should be planted so that the point at which the stems emerge from the root is 2" below the surface of the soil. Tree Peonies in a pot, like the one I bought, should be planted so that the soil in the planting hole is level with the soil in the pot. 

Planting a Potted Tree Peony:

Tree Peonies tolerate a variety of soil conditions but prefer a neutral to slightly alkaline soil with good drainage. You should dig a planting hole that is a least twice the size of the pot in width and depth. Place some dirt back in the bottom of the hole. This will allow your peony's roots to grow out into loose soil. Take your peony out of its pot and place it in the planting hole. It is recommended to amend your planting soil with some compost and a handful of bone meal. Backfill level to the pot's soil. Mulch the plant to help keep down weeds and to allow your peony to retain moisture. Water well.

Watering

Once established Peonies are pretty drought tolerant, but during the first growing season, it is important not to let your peony get too dry. When you notice your new Tree Peony could use some moisture, water it deeply. Try to avoid getting water on the foliage as it will encourage fungus.

Ongoing Maintenance

You can expect your Tree Peony to take 2 or even 3 years to settle in and bloom profusely. Remember these woody shrubs may take as long as 5 to 10 years to reach their full size. If this seems like a long time to wait, take comfort in the fact that peonies can live for 100 years or more. 

Transplanting:

Try to avoid moving a peony as the plant will grow slowly while the roots re-establish themselves. If you must move a Tree Peony, move it in the fall. 

Begin at least 18" from the base of your peony, and work in a circle, loosening the soil with a large garden fork. Lift and secure the root ball with a piece of burlap. Cut off any remaining leaves, being careful not to cut any of the woody stems which will be responsible for next year's flowers. Move the peony to its new location, remove the burlap and replant your peony. Water well. 

Unfortunately, it may several years for the peony to recover.

Fertilizing

Peonies don't need to be coddled, but they do benefit from regular applications of fertilizer and a top dressing of mulch. Mulch not only also serves to retain soil moisture, it helps to protect your peony through the winter.

In doing my research, I found recommendations that beginning in early spring of a peony's second year, it is a good idea to apply a fertilizer high in potash to encourage flowers to develop. A second and third application of a complete or organic fertilizer should be added after your peony finishes blooming and in mid to late fall. I think I will adopt this routine for all my peonies.

Pruning

Prune a Tree Peony in early spring just as the buds are swelling. Begin by removing any dead wood. Prune back to a live bud or just above ground level. Here is a handy link to a video on pruning a Tree Peony:

Pests and Diseases

Good news! Deer and rabbits won't nibble on a Tree Peony. The only problem you might encounter is peony wilt or Botrytis, which appears in early spring just before Tree Peonies flower. If any stems collapse or spots appear on the leaves, remove them to help stop the spread of the infection. Fungal spores can overwinter on old foliage, so a fall cleanup of all old peony foliage is an important practice to adopt.

If I pick the right site and take good care of it, my Tree Peony should well outlive me.  And I should be able to look forward to years and years of beautiful white flowers.

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