Cottage garden planting is usually herbaceous perennials and annuals, so things like hollyhock, delphinium, lupins and a host of annuals. Be warned though - without making a skeleton of evergreen and deciduous shrubs, you will be looking at bare ground covered with dead foliage all winter.

As Bamboo suggests you might need a few shrubs dotted along to avoid a barren winter look. There are plenty of articles suggesting plants that leave interesting winter shapes. Sedum Matrona leaves flat heads. Eryngium has thistle like heads that frost prettily and Phlomis russelina leaves strong tall stems with 3 pincushion shapes at intervals. Dipsacus fullonum (teasel) too. Good shrubs for early spring colour, that can easily be kept in order, are the smaller gold leafed Spireas. Hardy Fuschias are another good shrub, but cut back after the summer/autumn season. Good fillers are Heleniums and Day lillies. A really tall plant is Veronicastrum virginicum 'fascination' but takes time to get up to 5 foot, leaves good seed heads. So is Cardiocrinum Giganticum and leaves interesting seed heads

mite be nice to get some different shades of green fence paint which you can do with one dark green colour and a light emulsion . then just get your smaller paint brush out and paint uprightish stripes like thick grass on the fence then when the border grows up it will give the impression of going on for ever.