The most effective way to inhibit weeds is to plant something in their place. Weeds will grow on any open ground. But most weed seeds will not sprout on densely shaded ground. The best plants to shade the ground are groundcovers, shrubs & spreading perennials. Weeds are less of a problem in shade. But seeds will still sprout on lightly shaded open ground.
I don’t want to discourage you. But there will always be weeds. You must be vigilant: Pull weeds before they set seed! Weeds come from seeds. Plastic, rocks, gravel & bark will not keep weeds away forever. Weeds mostly seed in from above. Bark & other mulch will help to keep weeds under control for a time, while other plants have a chance to get established. Be sure you can distinguish weeds from the groundcovers you have planted.
To get rid of weeds that already exist, you should probably just pull them out. It will help if you loosen the soil with a garden fork, hoe or hook. Don’t be fooled into thinking that is the end of the weeds. There are undoubtedly still seeds in the ground. Keep watching for new weed sprouts.
Weeds with long, fleshy roots (like dandelion & bindweed) will grow back, if part of the root is left in the ground. This is also true for blackberry. It can be very difficult to get all of the roots of a blackberry vine. If it grows back, keep cutting it off at ground level. I don’t think that herbicide is any more effective than cutting.
This blog began in 2008 as metropolitan gardens to provide information on gardening in Seattle & places like it. Click on Gardening in Cascadia. It expanded to include Parks P-Patches Public Gardens in the US, Canada & Europe. Then Nature was added. (The only difference between garden & nature is intent.) Most recent posts are not about Seattle, or Cascadia. Many are Urban Landscape, mostly streetscape. Posts appear on 1st Friday & sometimes also on 3rd Friday.
The city of Seattle rests between 2 bodies of water: Puget Sound & Lake Washington. Puget Sound is a substantial part of the Salish Sea & a very small part of the Pacific Ocean. The Salish Sea is set apart from the Pacific by the Olympic Peninsula in the state of Washington & Vancouver Island in the province of British Columbia. The dense, wet clouds of the Pacific Ocean travel as far as the Cascade Mountains, near the Salish Sea & not very far from the ocean. East of the Cascades lies the desert of the Columbia Basin. The moist, temperate climate of Seattle extends south to northern California & north to southeastern Alaska. The Pacific Northwest Coast from San Francisco Bay to Cook Inlet shares a flora dominated by evergreen coniferous forest. The central portion, west of the Cascade Mountains, is called Cascadia. The climate is cool & wet from fall to spring, warm & dry in summer. The Olympic Mountains block Seattle from much of the Pacific rainfall. Seattle is drier than the Atlantic coast of North America & northern Europe, cooler in summer & warmer in winter. It lies near the latitude of Paris & Quebec City.