Fabric

• Use fabric to cover your pergola. Choose weather- and fade-resistant fabric made for outdoor use. This fabric is available at most fabric and some home improvement stores. For temporary shade or decorative covers, such as for a party or wedding, use any type of fabric desired, as it won't be subjected to the elements for more than a day. Choose light colors so the area under the pergola is still brightly lit with diffused light.
  
  Measure your pergola before purchasing the fabric. Buy enough fabric to cover the size of your pergola plus an extra 4 feet on either end. Weave the fabric in and out of the wood lattice on top of the pergola, securing it with ties if necessary due to wind concerns. This adds a decorative element as well as a useful way to block sun and moisture.
  
  

Natural Materials

• While it takes more time to achieve full coverage than just throwing a cloth over it, living plants provide additional shade and beauty to your pergola. Train vining plants such as wisteria or trumpet vines up the arms and over the top of the pergola. The flowers will hang down between the lattice adding to the garden charm.
  
  If you don't wish to wait for a vine to grow but still want to take advantage of natural elements, use branches and twigs to make a covering. Twig fencing is available at home improvement stores. Roll it out over the top of the pergola and secure with wire. Make your own version using cut branches from your property and wiring them to the top.
  
  

Clear Covers

• To keep the sun and view of the lattice top but block out rain and falling leaves, consider a clear cover for the pergola. Clear patio awning materials are available. Place them on top of the pergola and attach with wood screws to hold them in place. Lexan and fiberglass panels are other choices. Choose materials that are resistant to cracking and yellowing in the sun.
  
  To keep out leaves but still leave your view intact, consider wire mesh. This won't prevent sun or rain from coming through but will keep debris from falling on you or ruining the patio beneath the pergola. Purchase galvanized wire mesh so it won't rust in the elements.