She has a Bachelor of Arts degree in art with a minor in English. This insect has a very wide range of host plants, including box, and heavy infestations can cause a lack of vigour. JANE: Box Hedge leaves can turn orangey-brown because of high soil acidity (often caused by a build-up of added fertiliser) which locks up the nutrients. Many of these varieties are drought-tolerant and have good disease resistance. This sounds like poor drainage and water logging which can cause roots turning blackish and brittle trim damaged roots and trim bush also, then repot (as below). If its limited to leaves generally turning yellow repot in J I no3 with good drainage crocks in … Often brown leaves are caused by environmental factors, which can be remedied by paying close attention to … For best results, fertilize only once per year, in early spring. This tiny creature feeds by sucking sap from the undersides of the leaves, particularly during spring and early summer. Asked August 10, 2016, 3:13 PM EDT. The development of brown leaves on a prized plant can be a worrying discovery. Boxwood (Buxus) are wonderful evergreen plants to formalize the edge of a border with a low hedge or grown into a larger shrub to make topiary shapes. “Buxus turning brown.” It is dying. Brown leaves on woody plants. Since the temperatures have been so extreme, these shallow-rooted plants cannot draw any more water from the frozen ground to replace the water lost by the leaves. © Copyright 2020 Hearst Communications, Inc. In some circumstances, boxwoods may turn brown. Many trees need a significant amount of watering, especially if they're young or newly transplanted. This may be due to a soil-borne disease called Phytophthora root rot. Volutella blight is a disease of box caused by the fungus Pseudonectria buxi. Buxus is an evergreen plant which never loses all its leaves. Learn about how our products can help you. Like most plants, the boxwood will struggle to survive if its roots are damaged. Amend heavy clay or poorly draining soil with peat moss or compost to keep the leaves of the hedge from turning brown. Can I use some sort of hormone to bust them up? Remove all debris from infected plants. Water your boxwoods 1 inch per week. There are actually several reasons why this happens. Water in winter months as well, but cut watering to once every two weeks. Mon – Fri | 9am – 5pm, Join the RHS today and support our charity. Theyre plagued with a number of problems that can result in brown or yellowing boxwood shrubs. How to keep Buxus healthy. What to do about shrub leaves turning brown. Overfertilization may cause the leaves of your boxwood to become scorched at the edges, or entirely brown. When the leaves take on distinctive yellow tips or an orange or bronze colouration, it suggests the plants are under environmental stress. The females deposit their eggs amongst mounds of white waxy fibres that have a grooved appearance, these can be found on the stems and foliage. Spore masses, developing on undersides of leaves in wet conditions are pink for Volutella blight and white for box blight. Always ensure that all garden tools, particularly shears and clippers, are clean. The condition strikes plants receiving too much winter sun, especially when they're unprotected from frost or strong wind. Leslie Rose has been a freelance writer publishing with Demand Studios since 2008. However, boxwoods that develop tender new growth late in the season may be vulnerable. Box tree red spider mite is difficult to control. It is a weakly pathogenic fungus, resulting in numerous tiny black raised fruiting bodies found on dying or dead straw-coloured leaves. For gardeners growing boxwoods in temperate, coastal areas where frost is uncommon, this is generally not something to be concerned with. To control it either clip off the affected shoots or spray with one of the fungicides labelled for rust diseases.The fungicides tebuconazole (Provanto Fungus Fighter Concentrate), tebuconazole with trifloxystrobin (Provanto Fungus Fighter Plus, Toprose Fungus Control & Protect), and triticonazole (Fungus Clear Ultra) are approved for the control of rust diseases on ornamental plants. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place. Mussel scale, Lepidosaphes ulmi, is a sap-sucking insect that is found on a range of woody plants, including box, apple, hawthorn, ceanothus, cornus and cotoneaster. The adults emerge from the leaves, leaving an emergence hole where they exited. The lower leaf surface develops a slight swelling in the area affected by the larva's feeding. Prevention Sydney is experiencing a clear winter at present, with recent weeks of very strong and gale-force winds. There is no known cure for this problem; infected plants and roots must be removed and discarded, not composted. This insect causes the leaves to become cup-shaped and in spring there are splashes of a waxy white material on the foliage which can also be blown around in the wind. Unfortunately, there is no point applying fertiliser in winter months so you must be patient until the warmer weather arrives in mid-October. The box leaf-mining gall midge, Monarthropalpus flavus, is uncommon in Britain but occasionally feeding damage is observed.