…is not even a question. I love berms, and everything seems to grow bigger and better in a berm than in flat ground.
The moles are industrious little fellows. Whenever it rains, or wherever we water, this is a typical scene of their work. I might scoop up the light, fluffy soil as many as four or five times, only to have them push up another mound. I could grind my teeth and hurl expletives their way, but instead I praise my little crew for providing me with a steady supply of material.
Above is a shot of a berm in the early stages. I know, at this point it looks like a burial mound. Weeds, clippings, hunks of dirt from edging beds, etc. get dumped here until it reaches a height and shape that appeals to me, bearing in mind that it will settle over time and flatten to maybe half its height. It will then get a thick mulch of newspapers. I work with about ten layers at a time, watering thoroughly so they will lay down and stick together. There must be wide overlapping, or else grasses and weeds will find their way through the mulch. I extend the papers a couple of feet onto level ground, then border the mound with rocks. Cliffs line the roadway from our place into town. I hailed a highway patrolman one day to ask him if it was permissible to pick up fallen rocks along the verge. His bemused reply was that he didn’t see why not, as long as my car was parked well off the traffic lanes. I now stop frequently to load up the floor on the passenger side with the largest rocks I can find.
So that is a berm ready for planting, with just a couple of plants in place. The rock border does double duty: it holds the newspapers in place, and holds back the soil from migrating into the paths. Here’s where those molehills come in. Each time I get a wheelbarrow loaded up with mole dirt, I add a couple shovels full of corn gluten meal to counteract the weed seeds I know are lurking in there. The mixture is spread over the newspapers until nary a headline is visible. When a plant goes in, I just poke a hole and cut away enough to dig a proper hole. Eventually there will be little sedums and such creeping between and over the rocks. Cedar shavings cover the paper mulch outside the rock border to create a path and prevent surrounding grass from encroaching on the berm.
The above berm is further along, with plants beginning to fill in. I am experimenting with ground covers here, but even with quite a bit of bare ground, the weeding is much easier to manage than in the in-ground beds. The few weeds that do appear are usually shallow-rooted (catch them before they penetrate the paper mulch) and easy to pull out.
The first berm, on the east side of the house, is beginning to get a little crowded. It has been promised a round of dividing and pruning come spring. Restraint is a hard lesson, and that new, currently bare, berm is bound to fill up fast…especially with the HPSO fall plant sale coming up.
So there you have it: my formula for berm building. Best of all, all materials discussed here were absolutely free. More money for plants!