Applying mulch
Mulch keeps the soil cool in summer, controls weeds, and adds nutrients and organic matter as it decomposes (if you use organic mulch). For flowerbeds with perennials and annuals, spread 3-5 cm (1-2 inches) of organic mulch (shredded leaves, buckwheat hulls, cedar mulch, and so on), adding to it as necessary to maintain this level. For alpine plants, use an inorganic mulch such as fine gravel. Keep the root collar of the plants free of mulch.
Tilling the soil
Repeated rain and watering eventually causes a crust to form on unmulched soil surfaces. Regular tilling loosens and aerates the top layer of soil, makes it easier for water to penetrate and eliminates weed seedlings. This garden maintenance chore reduces water evaporation by breaking the small capillary channels that draw moisture to the surface. Make a habit of tilling your beds once a week. Work in such a way that you don’t walk on any freshly turned soil. If you have applied mulch, tilling is unnecessary.
Controlling weeds
The best way to get rid of weeds is to pull them out by hand, making sure to remove as many of the roots as possible. It is best to pull weeds when the soil is moist and crumbly. If the soil is too compact, use a small garden fork. Eliminate weeds before they produce seeds.
Removing faded blooms
Some perennials stay more attractive and bloom for a longer time if you deadhead them, removing faded flowers before they go to seed. Others produce very attractive seed heads that are worth leaving on the plant all season long. As well, some perennials and biennials self-seed readily. If you like the natural look this will create, go ahead and let them do so!
Tip for perennials
Remove flowers and flower stalks back to the first healthy-looking leaf.
Some plants that bloom longer or more prolifically if deadheaded:
Achillea, Alcea rosea, Anthemis tinctoria, Astrantia major, Campanula, Chrysanthemum, Coreopsis, Dianthus allwoodii, Dianthus gratianopolitanus, Hemerocallis, Lupinus, Malva alcea, Mimulus, Monarda didyma, Penstemon, Phlox paniculata, Salvia nemerosa, Scabiosa.
Some plants with attractive seed heads:
Allium, Astilbe X arendsii, Echinacea purpurea, Iris siberica, Liatris spicata, Papaver orientale, Rudbeckia fulgida.
Some plants that self-seed:
Achillea millefolium, Coreopsis verticillata, Digitalis purpurea, Digitalis grandiflora, Echinacea purpurea, Euphorbia polychroma, Lupinus, Malva alcea, Solidago.
Tips for bulbs
Tulips, paperwhites, daffodils and various other bulbs will be more attractive and will store up more nutrients if you deadhead them before they go to seed. On the other hand, the seed heads of some bulbs, like decorative alliums, are very attractive and worth keeping.