Gardening, George, Grow Your Own, Hedging, How To, Plants

Caring for topiary

Growing topiary is one of the most magical arts you can master as a gardener. We all love the huge hedge animals and blooming box clouds. But maintaining and caring for topiary plants can be a lot of effort, so we’ve broken down the steps into our top tips. Keep this checklist handy as you get to work on your creations!

  1. Plant your high hedges wide as they’ll need a lot of root space.
  2. Topiary needs aerated soil so make sure it doesn’t become waterlogged. Use good compost, bark mulch and grit.
  3. Feed your plants with slow release fertiliser granules, and Growmore once every spring.
  4. Water regularly over summer and give a light watering in winter.
  5. Sterilise your cutting equipment with antibacterial spray to avoid transfer of disease.

Clipping topiary hedges

  1. Clips your plants into shape once or twice a year. During summer is the best time to do this – start after frost season is definitely over and finish up by September.
  2. Only cut the topiary on an overcast day as bright sunlight will scorch the leaves.
  3. Experts recommend trimming first with power tools for speed, then cleaning up with sharp shears.
  4. If you’re training growing branches then use soft twine so it doesn’t cut into the wood.
  5. Watch out for signs of disease. Box hedges are particularly affected with box blight and box suckers. Yew can be hit with phytophthora root rot.
  6. If your topiary has been neglected then hard prune it in early spring to get it back into shape. Then give it plenty of feed and mulch.

Topiary maintenance

We hope these tips will get you started on the path to topiary perfection. If you have any other points on how to care for topiary then please share in the comments below!

George at PrimroseGeorge works in the Primrose marketing team. As a lover of all things filmic, he also gets involved with our TV ads and web videos.

George’s idea of the perfect time in the garden is a long afternoon sitting in the shade with a good book. A cool breeze, peace and quiet… But of course, he’s usually disturbed by his energetic wire fox terrier, Poppy!

He writes about his misadventures in repotting plants and new discoveries about cat repellers.

See all of George’s posts.

Hedging, Jorge, Plants

alternatives to buxus

Forgoing box is a real shame as it possesses all the characteristics required for low maintenance natural hedging. It responds well to clipping, and is slow growing, often needing to be cut only once a year, with growth usually between 10 and 15cm. It is also frost resistant and native to the UK, being cultivated since at least Roman times. Sadly, due to the current box blight epidemic, box is no longer the premium option, as the disease can destroy years of work to which the gardener can do little to stop. However, using other plants can be seen as a great opportunity to experiment, which makes gardening so enjoyable in the first place. There are so many underappreciated alternatives that can produce stunning delineated gardens.

Obviously, no plant will be exactly like box and the shape (and colour) of your hedge could be very different. If you wish for a substitute for box, however, Privet (Ligustrum ovalifolium) is a highly popular choice that is extremely hardy and small leaved, although sadly fast growing; henceforth, it will need to be trimmed multiple times in the summer to encourage dense growth. As it is only semi-evergreen, there is also the possibility of the plant shedding its leaves in extreme bouts of cold. Another possibility is switching to artificial topiary that is visually identical to box, and virtually indestructible, although its shape is limited to the manufacturer’s designs.

alternatives to box

Other worthy alternatives include the Griselinia littoralis, Euonymus japonicus and Elaeagnus ebbingei. The Griselinia is notable for its soft glossy leaves, average growth rate and responsiveness to clipping. The Euonymus is usually two-tone with cream bordering the edges of its otherwise green leaves, although it can variegate greatly in full sunlight. The plant is hardy and suitable for nearly all soil types, although will need maintenance to ensure denseness. The Elaeagnus is a great alternative as it is dense, hardy and responsive to clipping. It is also fragrant in the autumn with the emergence of white flowers.

One of the best species of natural hedging has to be the Taxus baccata, commonly known as the English Yew or Common Yew; it is very hardy, average growing, dense and great for birds, which love its berries. For more colourful alternatives, lavender (Lavandula angustifolia) and sometimes heather, can be grown into hedges. Key for lavender is to cut it before it flowers, or otherwise it will lose its shape. It is great for wildlife, fragrant and evergreen.

common yew

Due to the box blight epidemic, the RHS Garden Wisley are currently trailing 25 alternatives to boxwood. The varieties that have performed well include such plants as the Kilworth Cream (Podocapus nivalis), Sunshine (Ligustrum sinense) and Tom Thumb (Pittosporum Tenuifolium). The team has found that the Podocapus versatile, and responsive to clipping; the plant itself can be described as extremely small leaved, and darker in colour than box. The Ligustrum is slow growing with vibrant yellow leaves, the Pittosporum purple and compact. Also of interest is how the Pittosporum is a source of food for animals in its native New Zealand and is thus hardy and responsive to clipping.

Do you have any experience growing hedges? We’d love to hear from you. Post in the comments below!

Jorge at PrimroseJorge works in the Primrose marketing team. He is an avid reader, although struggles to stick to one topic!

His ideal afternoon would involve a long walk, before settling down for scones.

Jorge is a journeyman gardener with experience in growing crops.

See all of Jorge’s posts.

Gardening, Hedging, How To, Jorge, Pest Control

treating box blight

Ever since the 1990s, gardeners have had to witness the destruction of their natural hedging projects due to the emergence of new fungal diseases targeting Boxwood (Buxus sempervirens). This has only been exacerbated with the introduction of the Box Tree Caterpillar (Cydalima perspectalis) that began appearing in gardens since 2011. (It was likely imported from the Far East in 2008.) This has affected many famous gardens and gardeners with even Monty Don witnessing the decimation of his 15 year ornamental hedge project. The blight is so deadly that the preferred option for many gardeners is to simply destroy the affected plants, as even plants that appear to recover are often destroyed with the re-emergence of the fungus. Others have abandoned Box entirely by switching to Box alternatives. However, one need not abandon box altogether as both problems are preventable and treatable, although the blight requires great time and effort to combat. Other less common problems include: Box Rust, Box Sucker, Box leaf-mining gall midge, box red spider mite and mussel scale.

Treating Box Blight

The two most serious forms of Box blight are Cylindrocladium buxicola and Volutella buxi, which often appear together. The former is highly destructive and can kill a plant in a matter of days. It is characteristic for producing discoloured leaves that are white on the underside with brown lesions on the top. In humid conditions, the fungus may result in black streaks on stems. The latter turns leaves yellow, darkening them to a shade of tan. How they enter the plant is also different as the Cylindrocladium enters through leaf cuticles in humid weather, while the Volutella requires a cut leaf surface. Both diseases are treated together with the same methods, although favourable growing conditions may allow the Box to recover from the Volutella without such an intervention.

Treating Box Blight is difficult, but can be done, although there is no guarantee of success, and it may be preferable to simply burn the affected box to safeguard the rest. Key is to prevent further contamination through disinfecting your tools, along with your clothes and boots that sticky spores can attach. We recommend that you use liquid copper to clean your tools. (It will kill the spores.) Now with the affected plant, it will need to be hard pruned in the affected areas, the branches burnt. The cut areas will then need to be treated with fungicides that contain tebuconazole or tebuconazole and trifloxystrobin. Any leaf debris should be picked up and destroyed and the top layer of soil removed and replaced. (Spores can stay in the soil for a whopping six years!) We recommend that you do not use fertiliser, as high nitrogen produces vulnerable growth. Instead, mushroom compost can be used as mulch to provide aeration and better microorganism balance. Finally, important to note is how the diseases are suited to humid conditions where air movement is restricted. Therefore it may be necessary to open up the compact framework of your box – a process known as halting clipping.

If you are unaffected by blight yet, or wish to prevent blight from entering new areas of the garden, prevention is better than adaption. When bringing in new box keep it quarantined and watch for symptoms. To do this, you can either leave it for six weeks untouched, or create humid conditions and leave it for 3 weeks. As the fungus thrives in such conditions, the blight will appear by then. (Sadly, some nurseries use fungicides to hide such symptoms, so it is necessary to be cautious.) Again, preventing humidity is key, and can be achieved through watering at the base of the plant rather than at the foliage, and by positioning the Box away from overhanging plants. Also important is not to clip when rain is forecast, or the plants wet. Finally, it is recommended that you provide adequate ventilation for better airflow, spacing the Box around 30 cm apart from each other.

A Look to the Future

buxus

For now it appears that box blight will run rampant over gardeners’ painstaking creations, but there are a number of blight resistant cultivars being developed in Europe that should appear on the market in a few years.

Treating Box Rust

Box rust (Puccinia buxi) is another common problem that affects Box and is symptomatic for orange pustules on both sides of the leaves. It is usually harmless and is treated through cutting off the affected areas or using fungicides for rust diseases such as tebuconazole, tebuconazole with trifloxystrobin and triticonazole.

Stopping the Box Tree Caterpillar

stop box caterpillar

The Box Tree Caterpillar can leave patches of dieback much like box blight, and is distinctive for patches of webbing and frass droppings. Young Caterpillars are greenish-yellow with black heads, while the older ones have thick black and thin white stripes along the body and are up to 4cm long. Like most insects, they are most active during the warmer months, but can overwinter in webbing spun between leaves. To deal with them, they can either be picked off by hand, or dealt with insecticides that include ingredients such as pyrethrum, deltamethrin, lambda-cyhalothrin, and acetamiprid. (It is recommended that you do not spray plants in flower as this could deter potential pollinators.) Like box blight, prevention is preferable to adaptation so it is recommended that you check new plants in nurseries.

Other Box Problems Caused by Insects

  • The Box Sucker (Psylla buxi) can distort your box by turning the leaves into mini-cabbages. (Oh, No!) The insects suck the Box’s sap and leave chemicals that retard new growth. It is not usually serious, but can be controlled with the above insecticides and clipping.
  • The box leaf-mining gall midge (Monarthropalpus flavus) effects Box through causing a yellowish discoloration of the leaves. This discolouration is caused by the fly’s larvae that hatch and feed inside the foliage. It is, again, unserious and not usually worth treatment.
  • Mussel scale (Lepidosaphes ulmi) are tiny mussel shaped sap-sucking insects that usually attach to bark, but on occasion will appear on leaves. Small infestations are not worth treating, but larger infestations can be treated with the above insecticides or organic sprays such plant oils. Such treatments are best applied in May and June when the next generation is emerging and vulnerable.  
  • The box red spider mite (Eurytetranychus buxi) is another sap-sucker that feeds on the undersides of leaves, causing a fine white mottling. While the mites are difficult to exterminate, they do not seriously damage the plant; the bugs can be treated with fatty acids and plant oil sprays applied continuously in five day intervals until the all the life-cycles of mites are wiped out.

Have you had trouble with box blight? We’d love to hear how you coped. Post in the comments below!

Jorge at PrimroseJorge works in the Primrose marketing team. He is an avid reader, although struggles to stick to one topic!

His ideal afternoon would involve a long walk, before settling down for scones.

Jorge is a journeyman gardener with experience in growing crops.

See all of Jorge’s posts.

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