There are companies that specialise in outdoor weddings; they have the services and equipment, and probably a lot of good advice about details you never thought of.
Aisle marked out with flowers, or a carpet, or lanterns on a pole, or just covered with petals.
Decorate so that the place where you take your vows is the place where everybody focuses their attention.
If the members of the wedding party are to stand in a certain place have it marked out. Use flat stone/cement blocks for each position; it helps prevent shoes from being ruined by the grass.
Calculate where the Sun will be during the ceremony, and make sure you arrange events so that it is not shining in everybody’s eyes.
Decorations that can be moved easily. Wire structures with flowers; Wishing well barrel; artificial hedges; gazebo; pedestals; alters.
For Hot weather have a drinks cart.
Also for hot weather, attach the programme to a short stick so it can be used as a fan.
Hire a large outdoor fan to keep people cool.
Find a way to include shade.
Provide sunscreen, preferable in small, individual packets.
Bulk buy some sunglasses for the guests
Put some plants around that naturally repel insects. Get some repellent bands for your guests. Burn some repelling candles.
Have someone keep any flowers and plant hydrated with a spray gun
There are some perfumes that act as pest repellents.
For cold weather provide seat cushions and small blankets.
Use soulmates on high heels to prevent your shoes from sinking into the grass, little plastic caps for heels.
Put small weights in the hem of any clothing item that might be blown about in the wind.
Let the catering company know the location and plans right from the beginning, including the backup plans.
Glass terrarium to protect food, especially the cake!
Can people at the back hear? An audio system is probably necessary for anything bigger than a few people. This requires power.
If you have live music and/or a DJ that will also require power; consider 3 phase and a generator for large affairs.
Hand up a photoframe from a tree, and have people photographed through it.
If it continues till night time have creative lighting ideas. Put lights under tables so the tablecloth glows. Have Chinese lanterns. Glow sticks. Mix glow stick liquid with blow your own bubbles and have luminous bubbles.
Local wildlife occasionally wanders into the picture. Not sure what to do about it. Just find a good anecdote to tell your children about latter.
Permits are necessary for some places. Don’t neglect this. One party that forgot this had their reception interrupted by the garden’s automatic sprinkler system!
Rain! Have a backup plan. Dedicated wedding venues almost always have this.
