When to Prune Shrubs - Pruning Calendar for shrubs.

Buddleja hard pruned in spring - ready to send a lot of new growth and large flowers.

The shrubs mentioned in this calendar for pruning do NOT HAVE TO BE PRUNED in many instances. These are simply optimum times if you so wish. For instance, some of the evergreens are best pruned back by mid summer in order that they gain sufficient 'hardy;' growth before the onset of the following winter..You will soon be aware of why 'when to prune shrubs' is as important as 'how to prune shrubs'.

 Pruning is necessary for some shrubs - not because they actually need it, but more because we have either planted them in the wrong place, or they are simply not conforming to what we think they should look like. But if you are going to prune, it is essential that you know when to prune shrubs, for if you prune some shrubs at the wrong time, you can lose flowers for a year or maybe two.

There are many other shrubs that simply need pruning to do their best for us - whether new lush foliage, stems or flowers. The downfall of pruning in many cases - certainly as our mailbox suggests - is that many shrubs are pruned at the wrong time.

This results in either cutting off the flower buds for the season - hence no flowers for a year; cutting off the stems in autumn which would normally give us a great display through the winter; or even pruning some types of shrubs/trees at the wrong time of year, which then allows fungal spores to enter!

Buddleja Pruned Hard in Spring season

When to prune your Shrubs - Calendar Of Pruning For Shrubs and Hardy Plants.

One of the problems of writing a Calendar of Shrub Pruning, is the fact that every year brings seasons which are either earlier or later than usual - particularly spring and autumn, and of course, being a world wide website, there will be different hardiness zones in different countries, together with different general climatic conditions which will also affect the optimal timing of any pruning for some types of shrubs. This can affect the time when you prune your shrubs. You will have to gain knowledge about your own particular time zone to know this.

The basis of our calendar, is that of minimum average temperature of approximately -7deg. This corresponds to most areas within the UK. It is roughly equivalent to Group 8B on the USDA Hardiness Zones Table. As with all things in life, times change. So do temperatures - regardless of your feeling about global warming.

The calendar below will be added to.

January - February Pruning

February - March Pruning

  • Hydrangea PG (Paniculata Grandiflora) and arborescens - quite hard pruning.
  • Sambucus foliage types, can be cut back hard to induce good growth stems and foliage.
  • Cornus alba and stolonifera types - together with sanguinea can be cut back hard to get plenty of stems for next winter spectacular.
  • Pruning Wisteria - Mid February is best.

March - April Pruning

  • Evergreens General Pruning if needed. Some flowering evergreens will need to be pruned at different times. As a general rule, evergreens should not be pruned when dormant.
  • Prune Garrya elliptica as soon as finished flower tassels
  • Chimonanthus praecox - The Wintersweet. Right after flowering - but minimal.
  • Honeysuckle - the winter flowering bush types - Lonicera fragrantissima etc.
  • Caryopteris x clandonensis should be hard pruned at this time
  • Viburnum x bodnantense types - as soon as finished flowering. Cut out 25% of the old stems to ground level each year to keep the shrub looking tidy, and youthful.
  • Hard Pruning and Rejuvenation of old shrubs - End of March Easly April

April - May

  • Hamamellis mollis and other Witch Hazels - but only if you have to!
  • Forsythia - All types right after flowering.
  • Jasminum nudiflorum - the Yellow Winter flowering type. Cut back hard if you wish.
  • Kerria japonica - right after flowering, and cut some of the branches down to near ground level. If you are really brave you can cut the whole shrub down hard! It will reward you with some great lush foliage - and flowers for next year of course.
  • Pieris. Especially if there was frost damage to the new foliage. Don't be afraid to cut back to regenerate - and get some new coloured foliage.
  • Chaenomeles - Quince - As soon as flowering finished.
  • Salix caprea and others that are grown for their pussy willow catkins.
  • Fatsia japonica - is best pruned in late April - May once frosts are over. Winter damage cut out, and cut beck for renewed foliage, and flower for the coming winter.
  • Deciduous Winter Flowering Viburnums - V. bodnantense

May - June

  • Weigela -  Unless still in flower. The foliage types can be cut back hard - ie W florida nana and W foliis purpurea
  • Photinia Red Robin for some extra foliage colour, and especially now if you want flowers in the next year.
  • Euonymus Evergreen types - Can be pruned now through to end July for better foliage effect.
  • Camellia - the Sasanqua types - early in May/June - after all flowering finished.
  • Camellia - Japanese types - C. japonica
  • Daphne - Evergreen types such as Daphne bhuolua. Only corrective pruning really.
  • Forsythia should have been done early May, but still ok now.
  • Fothergilla - Only if you have to. Minimal unless wanting to regenerate.
  • Lilac - Syringa - Dear head or prune back as soon as you can after flowering.
  • Kalmia latifolia - probably in June, but right after flowering has stopped.
  • Spiraea - the varieties that have already finished flowering in spring. NOT the summer flowering types
  • Viburnum evergreen and Deciduous types - spring or late winter flowering types such as V. tinus and V davidii.

June - July

Pruning at this time of year is normally confined to shrubs that flower on growths that were produced in the previous year. Therefore by pruning now, you are giving the plant time to produce new growth this year, which will also bear the flower buds for next year. Leave it too late, and there will be no time for the shrub to produce next year's flower buds. For this group of shrubs - prune immediately after flowering.

However, there are also several evergreens that can be pruned at this time - if they are simply being grown for foliage effect.

  • Flowering Cherry and Almond Trees - Prunus
  • Evergreen Azaleas - as soon as finished flowering, but only if they need it for shape or size.
  • Deciduous Azales will need pruning - dead heading in July.
  • Rhododendrons - best only to dead-head the old flowers, then you will see the new shoots directly beneath the old flower trusses.
  • Kolkwitzia - The Beauty Bush, right after flowering.
  • Deutzia - All types right after flowering.
  • Gardenia if you are lucky enough to live in an area of the world where they grow outside.
  • Hydrangea - Oak leaf type - Hydrangea quercifolia -minimal, but will ensure good autumn - fall - foliage.
  • Philadelphus - Mock Orange. All types right after flowering.
  • Osmanthus - after flowering best.
  • Pyracantha - Firethorn can be spur-pruned, or simply cut back to the old faded flowers. These will bring you the berries this autumn - fall - so don't cut them off.
  • Roses - The climbing types - after flowering finished.
  • Calycanthus - Carolina Allspice, or Sweet shrub - Right after flowering
  • Itea ilicifolia - unless still in flower
  • Elaeagnus pungens maculata and limelight, can be pruned back to 'refresh' the foliage if required, or quite hard to re-juvenate the plant. No later than end of July.
  • Corylus avellana Contorta, may be re-juvenate by pruning back hard by end of June preferably. This will give some new contorted growths and clean up the fi=oliage that tends to get messy around now!
  • Cotinus Royal Purple will benefit from cutting back hard to force another flush of vibrant foliage.
  • Holly - Ilex best to do any pruning for foliage by end of June - very early July latest.
  • Junipers - the low growing types. Last pruning back time this month.
  • Laurels such as Prunus Otto Luyken, can be cut back now at latest.
  • Photinia Red Robin can still be cut back for new foliage effect.
  • Pittosporum - all varieties. Prune as required.
  • Yew - Taxus spps. Last time for pruning back hard.
  • Myrtus - Myrtle - Would have been better earlier in the year, but can be pruned quite hard now.

July - August

  • Itea ilicifolia. Maybe earlier if flowering is over.
  • Leucothoe. The Rainbow type responds well to a hard cut back (for foliage) the others just minimal.
  • Osmanthus - if you missed out in late June.

August - September

September - October

October - November

Winter Pruning Wisteria should take place in October or November

November - December

December - January 

 

By David Hughes - info@gardenseeker.com