Physical stump removal is the best solution. Ideally the stump should be removed entirely, but if this is not possible alternative methods usually give satisfactory results.
For smaller trees the stumps can be pulled out with a winch. These can be hired by gardeners with the knowledge to use them safely. For leverage it is necessary to leave a good sized stub on the stump (up to 1.2m (4ft) high) rather than cutting it off at ground level.
Grubbing out by hand or mechanical mini-excavator removes the majority of the root system. Removal is easiest if trees are cut down so that a significant length of trunk remains to give leverage to help in removal. Landscape contractors are often skilled at stump removal, but you can hire mini-excavators and operators separately.
Alternatively, machines known as stump grinders will mechanically grind out the main root plate, leaving fine sawdust. Although stump grinders can be hired, they are potentially hazardous and are only for gardeners confident that they can use machinery safely. Some roots will inevitably be left in the ground but the majority should eventually rot down.
It is worth specifying how deep you would like the stump ground to. Shallow grinding, 20-25cm (8-10in), is normally sufficient for laying turf, but you should allow for deeper, 30cm (1ft), or more if replanting or landscaping. Also think about what you want to do with the sawdust. It can be left to fill in the hole, used as mulch in other areas of the garden, or taken away by the contractors. Specify which of these you would prefer before the work is started and be sure to have any diseased wood removed completely.
Should you like to replant the area it is best to remove bulk of the sawdust and fill the hole created by stump grinding with topsoil. If larger amount of sawdust was accidentally mixed with the existing soil it is usually worth adding nitrogenous fertiliser prior to planting to counteract possible problems with nutrient lockup. For example, consider mixing in chicken manure pellets or sulphate of ammonia.
Methods to avoid
We do not recommend burning down stumps in situ. They are usually too wet for this. Applying nitrate fertilisers also does not improve their burning qualities, or speed up rotting, even though these fertilisers are oxidising agents.
How to apply stump killers
Stump and root killers currently on the market are those containing glyphosate (e.g. Scotts Roundup Tree Stump & Rootkiller, SBM Job done Tough Tree Stump Killer (soluble sachet only), Doff Tree Stump & Tough Weedkiller and Westland Deep Root Ultra Tree Stump & Weedkiller) or triclopyr (Vitax SBK Brushwood Killer).
- Always follow the manufacturer’s preferred method. This may involve treating the entire cut surface of the stump, drilling holes around the living edge of the stump to pour the granules into, or using a chisel or axe to make wedge-shaped incursions around the edge of the bark (often used for standing trees). These notches can then be filled with granules or brushed with the liquid weedkiller
- The best time to apply stump killers is from autumn to winter. Avoid treatment in spring and early summer when the sap is rising
- Apply a weedkiller directly to the stump, concentrating it in the outer ring of live tissue just beneath the bark
- Weedkiller is best applied to fresh stumps, as live tissue is needed for its uptake. If the stump is only a few weeks old, you may be able to expose live tissue by cutting the top off to expose a fresh-cut surface
Finally, cover the whole top of the stump with a plastic sheet to keep off the rain and secure in place.