In his handbook, On Guerilla Gardening, Richard Reynolds outlines campaign tactics. Here's a list of essential items in any would-be guerilla gardener's arsenal:
In its purest and simplest form, guerilla gardening is little more than scattering seeds in places where, with time, they will sprout to fill the air with colour and scent. Some veterans have even fashioned gun- or grenade-shaped 'bombs' of damp compost mixed with seeds.
The cheaper and hardier, the better. Choose varieties that can withstand cold, drought, neglect and abuse by pedestrians, road users and dogs.
Hidden time bombs whose impact returns year after year. Guerilla gardeners often fill their pockets with daffodil bulbs and pop them into neglected pots or around the base of trees on grassland as they pass.
Only natural chemicals, of course. For major planting attacks, take a bag of compost made from your own heap of recycled kitchen waste, or 'worm juice' - fertiliser made in a wormery fuelled with food waste.
Seed-bombing - the most basic guerilla gardening - requires no tools, but Reynolds recommends carrying at least a small fork to aggravate the soil.
If illicit planting is done mostly at night, a head torch is the best way to illuminate your work and it leaves you free to get both hands dirty. Some guerilla gardeners use their car headlamps to light up their activities.
This precious resource needs to be considered from the very start. Some plants fare well despite neglect, but most would benefit from a little watering, so a plot on a regular home-to-work route which can be regularly tended with a splash of water is best.