Knowing what to prune and when is crucial for enjoying the best displays across a garden. A common mistake is treating all plants the same, and you pay the price by missing out on stunning flowers.

While you can prune plants in October, the onset of fall is not a sweeping invitation to take the pruners to everything (though you should always use the best pruning tools when you do, like these Felco F2 pruners from Lowe's). One key group not to prune this month is spring-flowering shrubs and trees that flower on old wood.

You can remove dead or broken branches to keep them safe and healthy, but refrain from any major work – you’ll simply remove all the buds and may even leave the tree susceptible to winter damage. So don’t cut these plants back in October, because come spring, when there are fewer or no flowers, you’ll feel remorseful about being too eager with pruning.

The sight of the vivid yellow blooms of forsythia in late winter is always warmly welcomed – it is a sign that spring is on the way. Forsythia is one of the earliest shrubs to burst into bloom, from mid-February onwards, so don’t rob yourself of these adored early flowers by pruning in the fall.

Always prune forsythia as soon as the blossoms fade. Once it gets into late summer and beyond, it is too late to prune forsythia. You’ll remove lots of the buds that have developed all summer, those that are preparing to carry next spring’s bright flowers.

If there are any dead or diseased stems that need urgent attention, carefully remove them with a pair of pruners or loppers. These Fiskars power-level loppers at The Home Depot can cut stems up to 1.75 inches in diameter.

Most azaleas and rhododendrons flower in spring, though there are some that bloom in late winter and others whose season lasts well into summer. Each shrub will put on a display for only a few weeks, when it is covered in a mass of orange, yellow, red, pink, purple, or white flowers.

You want to prune azaleas and rhododendrons two or three weeks after the shrub finishes blooming for the season. This gives it the longest time possible to develop buds for next year’s display. If you wait too long and prune rhododendrons or azaleas too late into summer or fall, there will be fewer blooms next year.

Good fall care for rhododendrons and azaleas does include mulching the shrubs with pine bark or ericaceous compost that helps to make the soil more acidic. You can get a bag of all-natural pine bark mulch at Lowe’s.

If your shrub needs major pruning, such as to reduce its size, this can be done during dormancy. But do so with the realization you will be sacrificing next year’s flowers.

The sweet, floral scent of lilacs evokes the senses in spring and brings a romantic air to the garden. When you grow lilacs, they flower from mid-spring to early summer, depending on the variety and your climate.

It can be a short but satisfying display – unfortunately, deadheading lilac flowers doesn’t encourage another flush of fragrant blooms. As the season is relatively brief, you won’t want to risk missing out on next year’s flowers.

Always prune lilacs quickly after they finish flowering. They set their buds on old wood in the summer. If you prune once fall arrives, you’ll chop off those buds.

If your lilac needs some rejuvenation, you can prune in winter. Either cut all stems down to around 12 inches from the ground – which is the brutal choice and you’ll get no flowers next year – or remove one in three of the older stems each year over a three-year period to reinvigorate it. You’ll lose some blooms, but have some to enjoy.

Any old stems over two inches wide will need to be cut with a pruning saw, such as this strong RazorTOOTH pruning saw at The Home Depot that can cut wood up to eight inches wide.

Deutzia puts on a short-lived but profuse display of white or pink star-shaped blooms in late spring and early summer. Whether you plant compact varieties in containers or larger types in flower beds for structural and seasonal interest, pruning the shrubs at the right time is crucially important.

They flower on old wood and need pruning within a few weeks of the blooms ending. This often makes June or July the prime window for heading out and giving deutzia a trim. The shrub then has several months to produce new stems and buds that will carry the weight of next spring’s flowering.

You can take hardwood plant cuttings of deutzia in the fall if you want to propagate new shrubs. Take a few selected stems that have grown this year, but don’t take too many, as this will affect the flowering.

Weigela shrubs have colorful, nectar-rich, trumpet-shaped blooms from late spring to early summer. If you grow weigela, these flowers, which can be red, purple, or pink, make the shrub a great plant for pollinators, with bees, butterflies, and hummingbirds attracted to them.

If you have a weigela as part of a buzzing wildlife garden, you don’t want to risk there being a lack of these pollinator-friendly flowers next year. You do this by pruning weigela quickly after the shrub finishes blooming. Leave it until fall and you will be trimming off the buds that will burst into bloom come spring.

Red is known to be the best flower color to attract hummingbirds. If you want to add more red blooms to a pollinator garden, this live ‘Red Prince’ weigela shrub at Nature Hills will do just that thanks to its bright red blooms that are rich in nectar.

The Eastern redbud (Cercis canadensis) is a native North American tree that produces spectacular blooms early in late winter and early spring. The stems, branches and trunks are covered in pink or white flowers.

Due to the earliness of this vivid display, redbuds are one of the best trees for attracting hummingbirds and other pollinators at this time of year.

There is usually no need to prune a redbud tree regularly. However, if any shaping or structural work is required on the fast-growing flowering tree, it should be done quickly after flowering.

Any large-scale pruning work is best left for winter, but the blooming will be reduced. An extendable pole pruner, like this one from Walmart, helps to trim high branches in the tree’s canopy from the ground.

A flowering cherry is one of the best trees for spring blossom, with abundant white or pink flowers that can be single or double.

The tree bursts into flower for no more than a week or two, and the beauty of these specimens can be enjoyed in gardens of all sizes, with compact varieties (like this Snow Fountains weeping cherry tree at Trees.com) perfectly suited for small gardens and containers.

Part of growing and caring for a flowering cherry tree is understanding the right time to prune it. That time is after flowering, so it is often a job for June or July. Getting it done early in summer gives the tree lots of time to form buds for next spring.

Trimming in fall removes blossoms and also encourages new growth, but these stems won’t have time to harden and will be damaged by frost. This puts the entire tree at an increased risk of pests and diseases.

What to Shop

While you don’t cut these plants back in October, some trees are fine to prune this month. It can be a good time to do light work on deciduous trees to keep them safe ahead of winter. Our guide to trees to prune in October highlights seven trees worth checking this month for dead, damaged, or diseased branches, which you can remove to prevent issues during winter storms.

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