Hummingbirds prefer to feed from flowers that are in bloom and attract them rather then from feeders whenever possible. This is not to say that hummingbirds will not feed from your feeders because they will, but if given the choice of the natural nectar that flowers produce and homemade nectar solution, the birds will choose the natural nectar while it is most plentiful and readily available. The natural nectar that is found in the flowers is sweeter then homemade nectar solution and hummingbirds like the nectar to be extremely sweet.
Does this mean that you should not put out hummingbird feeders? Absolutely not. All I am not saying is that there will not be as as many hummingbirds at your feeders while the natural nectar supply is plentiful. The hummingbirds will once again begin to frequent your feeders as the various blooms in your yard begin to decrease and the natural nectar supply is not as plentiful as it was previously. Homemade nectar solution is very similar to that of natural nectar which is why the hummingbirds like it so well when the natural nectar supply is no longer plentiful.