The first thing you need to do is identify them! Maybe they don't produce flowers because you've been pruning them at the wrong time previously and cut off the flowerbuds...? Is there a gardening neighbour who might be able to identify them for you - or do you have pictures you can post or a more precise description of leaves and growth habit?

Lilacs, along with a lot of other large flowering shrubs, need to be pruned immediately after flowering. If you prune them later in the fall or in the spring, you'll cut off the next summer's blooms.

Some shrubs do well pruned in the spring. You really do need to find out what it is.

Most tree pruning can be done in very late winter (before you see green)or late fall when the plant is dormant. As Sheryl said the flowering shrubs (not fruiting ones) should wait until after flowers have died and before next yrs flower buds are set.
If you don't know what type it is but you know it gets ugly and scraggly in the summer, you don't care about flowers (if it is a flowering type) I would just go ahead and prune it now. Yrs ago before I knew about proper pruning times I used to prune a lot of things when they looked scraggly and rarely did I harm the shrub.
If you are really concerned about the shrub and how it will grow after pruning, hire someone to do it for you.
Tina

How do I identify the bushes in my yard. We jsut bought the house and came from condo living. We are so green at all this.

Sheila 1211 - hello from Ottawa, Canada's capital city. We are up to our knees in snow now - but the garden still looks pretty especially with the bright red cardinals at our feeders and the evergreens all covered in snow.

The best way to figure out about the shrubs on your property is to 1) ask neighbours, 2) call up your local garden club, 3) check with a nursery (bring a sample small branch with you) and of course, you can learn about them just by watching them for a year or so, if you are patient. A condo is not a place that I would want to live in, because I would miss gardening. You may be "green" but you sound interested - that's the most important thing. I bet if you spot a gardener working in the yard as you go around the neighbourhood, they will be more than happy to answer questions - most gardeners love to share - plants or wisdom. Good luck with your new garden!