You may need to restart a struggling shrub from the base.
Byline: Tim Johnson Chicago Botanic Garden
If your shrubs have a lot of dead on the top and thin growth, then look at the base of the shrub to see if there is any new growth flushing up.
If the top of the shrub is dead or very thin in its leaf development, and there is a good flush of new growth at the base, then it will be best to cut all of the old stems out now and restart the shrub from the base. Then the shrub will focus its energy on the new foliage developing from the base.
I have seen a lot of dieback and thin foliage on doublefile viburnums with many flushing up new growth from the base. Shrubs like these will benefit from this pruning now, even though you would be removing some live branches.
* Trees planted in lawns can benefit from a mulched ring to reduce competition with grass roots and keep mowers and weed whips from damaging trunks. If the tree is small, mulch out to the drip line of your tree. If this is not feasible, extend the mulch as far as you can. Even a 6-inch-wide mulched saucer will help protect tree trunks from serious damage. Do not mound mulch or soil around trunks because it is unattractive and can cause rotting at the base of the tree.
* Groom your borders to improve plant appearance and maximize flower production. Gently remove any dried or yellowed bulb foliage since the bulbs are going dormant and have already stored nutrients for next year's flowers. Many bulbs still have green foliage so it's best to give them more time to mature before cutting back. Prune off spent flowers (deadhead) on your annuals and perennials to encourage them to continue flowering. Remove yellow foliage to keep the plants neat and tidy.
* Mowing is one way to control weeds in a large, natural prairie area that is being established in your garden. Native plants typically develop their roots, not their foliage or flowers, in their early years, which gives weeds the opportunity to gain a foothold.
Mow weedy areas now at a high height to cut back the weeds and keep them from choking out the native plants. In small areas, weed by hand. You can also carefully spot-treat weeds with an herbicide.
* Tim Johnson is director of horticulture at Chicago Botanic Garden, chicagobotanic.org.