Lilac in downtown Toronto

(Question)

Hi,

I really love lilacs, and would love to plant one in my downtown TO backyard. It’s a relatively small space, but the location I have in mind would still get a fair bit of sun. I am interested in a tree, not a bush, again due to space restrictions. The soils in my yard – it’s in a newly build home, built on top of an old school ground – is very compact. Do you any advice as to what type of Lilac I should be looking for and whether this tree is even the right fit for my space? Thanks!!

(Answer)

Lilacs are shrubs that have been planted in Ontario since the first settlers. You can still hike in some areas and see a lilac blooming, surrounded by forest. You can, if you look closely, often  find an old foundation nearby – people planted the lilac near the door so they could smell the wonderful flowers as they bloom in late spring. You would also find that the flowers now are at the topmost part of the plant, as it stretches to the sunlight.

You are right, lilacs (Syringa vulgaris and the many cultivars) need full sun to display their best qualities in large numbers. Less than 6 hours of full sun, the fewer the flowers. Lilacs are shrubs, and the common lilac gets very large (4m); the Dwarf Korean lilac (S. meyeri ‘Palibin’) only reaches 1.2 m, but spreads to 1.5m or so.

Even so, treed form lilacs are the same as the shrubs, but are grafted to a standard (trunk) at the top, and are often used as an ornamental accent. They stay relatively short, and their spread is usually less than a metre. Weeping lilac (S. pubescens subsp. julianae ‘Hers’) is particularly ornamental, and the mauve blooms are abundant. Cut-leaf lilac (S. x laciniata) has lacy foliage, very different from most lilacs, and is disease resistant and quite heat tolerant. The blooms are pale mauve and fragrant.

There are many more, and you may have to approach your local garden centre and have them special ordered. So, if you have at least 6 hours of sun, these may be suitable for you.

 If you have some sun but mostly shade, you may have to consider a different tree/shrub. Both the weeping caragana (Caragana arborescens ‘Pendula’) and the cut-leaf weeping caragana ‘Walker’,  are lovely specimen trees that are under 2 m tall. Both sport gorgeous racemes or chains of yellow flowers in spring. They are quite tolerant of most soils, as well as part shade. Hydrangeas are often standardized, and can be found at most garden centres.  PeeGee hydrangea (H. paniculata ‘Grandiflora’) blooms cone shaped, white flowers that will stay all season and turn a pink/bronze colour.  Pink Diamond hydrangea  (H. paniculata Pink Diamond) sports pink flowers and will grow in moist soils.

Now, about your soil. Just this morning, I read Mark Cullen’s column in the paper, and he says he can’t say enough that amending soil with organic matter is the best thing you can do for your soil and what you plant there. Couldn’t agree more. Compacted soil is often a death knell for many plants, because people often just dig a hole, throw some good soil in, and put in the plant. It will be ok for the first year or two, but the roots have a hard time penetrating through the adjacent, compacted soil, and often goes into decline.

So, for all your beds, you need organic compost to amend that soil. Most come in 20 L bags, and that will amend about 1m square of your bed. Calculate how much you need – you might have to get larger quantities from companies that will supply it by the yard (1m x 1m x 1m) and deliver it to you. It might seem a big job, well, it is, but once you dig it into your beds, turning it all together, the nutrients and the open spaces between soil particles will allow your plants to thrive.