Supertunias not so super this year? You're not alone, Wendy

Each week, Susan Richards of New North Greenhouses answers your gardening questions. Have questions about your gardening needs? Please email her at [email protected].

Sharon: Hi can I take the old flowers from my lilac now or is it too late? Also my 3 cedars in front of my front deck have grown above the railings and is blocking my view to the road. Can I trim them back to below my site line? Thanks.

If you just remove the dead flower and NOT THE BUD BEHIND IT, you are fine. The best time to prune lilac is immediately after blooming.

It’s too late to prune the cedar down. Any new growth stimulated by pruning won’t have a change to harden off before winter. Prune it back in early April.  

Bill: When can I prune my Bloomerang lilac? It has gotten very big and is blooming again right now.

The best time to prune this lilac variety is immediately after its first flush of flowers have faded, usually sometime in June. Don't prune now as it has already set bud for next season's blooms.

Wendy: I'm disappointed that my planters of Supertunia petunias are looking so poor right now. I was very diligent about watering through the really hot summer weather. I did put slow release fertilizer into the pots in mid June. It was supposed to feed for 3 months.

We had a similar problem with our big pots of Bubblegum Vista and Fuchsia Vista Supertunias in the garden here at New North. That variety of petunia, as well as Wave petunias, are very vigorous growers that needs lots of fertilizer to stay healthy and blooming right through to fall. With the amount of hot, dry weather we had and the constant need to water, the pellets you used where exhausted prematurely.

The secret to keeping your plants spectacular to fall is constant feeding. Next time, use a water soluble fertilizer mixed 1/4 strength applied every week as you water.

These photos (above) show the one petunia planter that was fertilized regularly in comparison to the other ones that didn't get enough food.