Brilliant Ideas! Companion Planting!

Are you wondering what you can plant with mature lilac? You’d be surprised to know that there are a number of amazing plants that work well in the same garden as a mature lilac.

Pamela asked “Can I plant peonies in the same soil as a big lilac plot? I’ve tried hydrangea in the same spot, and they didn’t do well, little foliage and they didn’t flower.”

The Answer!

Yes, you can plant peonies in the same plot as a big lilac and yes, you can grow hydrangea there as well!

Here’s what you need to know!

The roots of a mature lilac extend out past the dripline (ends of the branches at the widest point of the shrub canopy) by at least 1 ½ to 2 times. It is important to understand the size of the lilac root zone because the mature lilac roots will take most of the water in this area, making soil conditions dry. If you are going to plant in the root zone of a mature lilac, the only solution is to provide extra water for new plants. This will mean you need to hand water new plants at least three times a week for the first growing season and twice a week in the second growing season. During times of drought or hot weather, you might need to water your new plants daily.

Roots extend out at least 1 1/2 to 2 times the size of the branches.

Here’s what I did!

Like Pamela, I have a mature lilac in my front yard. I’ve planted Annabelle hydrangea next to the lilac because I wanted summer blooms, and I really like hydrangeas. The Annabelle hydrangea took about three years to establish their roots. I only had small foliage and no flowers for the first couple of growing seasons. But I didn’t give up! I kept giving the hydrangeas extra water, and in the third summer, I was rewarded with blooms. As a side note, Annabelle hydrangea needs little or no fertilizer in the spring. Overfeeding Annabelle will produce weak stems, excessive leaf growth, and little or no flowers. You only need about four tablespoons per 4 square feet for Annabelle plantings. Hydrangea naturally requires a lot of water, especially in a sunny location, so you may need to water Annabelle’s daily.

Yes, you can plant a peony in the lilac plot. I have grown pretty pink lacey peony in the same garden as my mature lilac. I did have to cut through a few of the fine lilac roots to plant the peony; however, they both seemed happy.  Peonies aren’t too fussy. They like full sun and shelter from strong winds and don’t want to be planted too deeply. When planting container-grown peonies, make sure the roots are placed at the same level as in the pot when placed in the ground. If you bury peony roots too deep, you will have tons of foliage but no blooms.

Pink peony after the rain

Mature lilac garden design!

From a design perspective, planting peonies with lilac means lots of blooms in late spring but no blooms in the summer or fall. If you have the space in your lilac garden and want summer and fall blooms, here are a few of my suggestions for companion plants that work.    

Koi Avens (Geum)
Moses Fire Daylily
Fall Sedum. Butterflies love sedum
Kiwi Gull Monty Hosta
Blue Boa Hyssop

There are numerous flowering shrubs and perennials that work well as companions with a mature lilac. Most of the above perennials are available in a wide range of colours, textures, and heights. Try a few with your mature lilac to create colour through the seasons.

Happy Gardening

Lexi – The Gabby Gardener

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