what causes a lilac bush not to bloom

Caren White is a Chief Gardener and instructor at Home Gardeners School. She has been associated with Rutgers Gardens for over a decade.

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You've had a lovely old lilac bush-league in your chiliad for years, but lately it seems to exist blooming less or not at all. It looks healthy with no signs of disease or pests. And then why won't it bloom? There are several reasons why lilacs stop blooming. Fortunately, most of these issues are easily correctable.

Is The Lilac Getting Enough Sun?

First, take a wait at where the lilac is growing. Is it getting enough sun? Lilacs need full sun to bloom. Full lord's day is defined as at to the lowest degree 6 hours of direct sunlight each day. Are at that place surrounding trees that have grown and filled out over the years so that at present they are shading your shrub? Neither large copse nor large lilacs are hands moved.

The easiest fashion to allow more light to achieve your shrub is to call in a professional arborist to trim the surrounding copse. If your trees have non been trimmed by a professional before, their growth may accept gotten out of hand and may in fact be unhealthy for the trees. Limbs that are rubbing against each other or that are interfering with overhead wires need to be cut. The arborist will also "residual" the trees by pruning them to their natural shape with equal numbers and lengths of limbs all the manner around. This helps in storms and so that a tree is non weighted likewise much to one side causing it to perchance autumn over.

Another possibility to consider is to propagate your lilac. This saves you the expense of purchasing a new bush to plant in a sunnier location. The all-time way to propagate a woody plant is past cuttings. Select a branch that is neither besides old nor too young to make your cut. A quick exam is to try and curve the co-operative. If it snaps off, it is the right age. If it bends without breaking, it is too young. If it doesn't bend at all, it is too old.

Brand a clean cut on on the end of the co-operative that broke and dip information technology in rooting hormone. And so place that end into soil in a container. Go on your cutting moist, but non wet. If the soil is too soggy, the cutting will rot. Roots should begin to grade within 3 to 6 weeks. You will know that new roots accept grown because the cutting will be producing new leaves. Plants that don't accept roots cannot produce new leaves. One time roots accept formed and the cutting is growing new foliage, yous can transplant information technology into its new, sunnier home.

White Lilac

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Does The Soil Accept Too Much Nitrogen?

Next, you should bank check the soil surrounding your lilac. Information technology might take as well much nitrogen, especially if your lilac is growing near your lawn. Backyard fertilizers contain a lot of nitrogen. Nitrogen encourages the growth of foliage at the expense of flowers. That is why lawn fertilizers contain a lot of nitrogen. Fertilizers meant for apply with flowering plants accept less nitrogen. A soil test can tell you if there is too much nitrogen. Don't waste you money on a kit from the store. They are not accurate nor will they tell yous what amendments to add together to your soil. Call your local Extension office for a soil test kit and they will postal service one to you. The kit will comprise instructions for gathering a soil sample and a self-addressed envelope for you to use to mail your sample to the soil testing laboratory.

The laboratory will examination the soil and send you a report. The report will tell yous most the nutrients and micro-nutrients that are in your soil or missing from your soil besides as instructions on the amendments you need to correct whatsoever deficiencies. If the examination indicates besides much nitrogen, an easy way to rebalance the nutrients in your soil is through the utilise of mulch. Wood fries or sawdust are excellent ways to soak upward excess nitrogen from your soil.

Variegated Lilac

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Is The Lilac Pruned Correctly?

Pruning can be a reason why a lilac doesn't bloom if it is done incorrectly. Lilacs are considered shrubs or small multi-stemmed trees. There are 2 types of shrubs, ones that blossom on "new wood" i.due east. this twelvemonth'due south growth and shrubs that bloom on "old woods" i.due east. terminal year's growth.

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Plants that bloom on new wood flower in the summer or the fall because their bloom buds are formed on branches that abound during the current growing flavour. If you prune them in the spring, this will cause them to produce more branches and therefore volition have more flowers.

Plants that bloom on old wood blossom in the jump. Their buds were formed on branches that grew last twelvemonth. If yous prune them in the spring, you are pruning final year'due south branches which have flower buds on them. The result will be few or no flowers because you have cut them off.

Lilacs bloom on erstwhile wood. They should be pruned as presently as they stop blooming in the spring then that yous don't cut off next year'due south buds. Pruning is really skilful for them. Information technology forces them to produce more new branches then they will have more flowers adjacent year.

Pruning your lilac in the fall is just as bad as pruning information technology in the leap. You take chances removing branches that have formed next year'southward buds. Always clip correct after your shrub has finished blooming.

Removal of dead or diseased branches tin can be washed any time. It's a expert idea, though, to check your shrubs in the spring before they foliage out when information technology'due south easier to run into which branches are salubrious and which are dead or diseased and need to be removed.

Try The Three Year Rejuvenation Plan

Your lilac sits in total sun, has bully soil and is never pruned in the spring or fall and information technology still won't blossom. At present what? A healthy lilac tin can live a long time. Somewhen its branches get also quondam to flower. Information technology'southward fourth dimension for a three year rejuvenation plan.

The first year, after it finishes blooming, remove 1/3 of the oldest, thickest stems. Cut them off right at the base of the bush. This encourages new growth because the plant is trying to supercede what you have cut off. This new growth will likewise take new buds which will be beautiful flowers the post-obit jump.

The 2nd year, prune away half of the remaining erstwhile stems. Some other flush of new growth will occur. The third yr, prune away the residual of the old stems for yet another flush of new growth. At the finish of the three years, you lot will have a salubrious, new lilac bush that will produce loads of flowers for years to come.

Questions & Answers

Question: My lilac buds up so the birds take a blast. Why?

Reply: Birds practise not consume lilacs. What they are after are the insects infesting your lilacs. Information technology is the insects that are causing the damage. Common insects that damage lilacs are lilac borers, foliage miners and mites. Insecticidal soap will kill the mites. A systemic insecticide volition kill the leaf miners. The insecticide permethrin will kill the lilac borers.

Question: What kinds of lilacs tin nosotros grow in Zone 9?

Reply: The problem in zone 9 is that your winters are not cold plenty for lilacs. Try some of the newer varieties that have been bred specifically for warmer climates: "Lavender Lady", "Angel White", "Excel", "California Rose", "Esther Staley", "Blue Skies".

© 2012 Caren White

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Source: https://dengarden.com/gardening/Lilacnolongerblooms

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