Your tulips are waning or they have already dropped their flower petals.  Same for daffodils, narcissus, crocus and the like.  Now relax.  Let the sun do its work: the leaves of each flowering bulb converts the energy of the sun into natural plant sugars and pushes that energy down into the bulb for storage until flowering time next spring.  This is a good time of year to add some Holland Bulb booster to the root zone of your bulbs to help them beef up for next spring.

When the leaves have turned yellow, time to cut them off at ground level and forget about them until next spring when they arrive once again.

Summer flowering bulbs are a different thing entirely… dahlias, tuberous begonias and gladiolas are not technically 'bulbs' but corms and tubers.  All you need to know is that now is the time to get them into the ground or into containers for a summer full of colour.  Each of these loves heat.  With glads I plant them each week for 6  weeks to get a succession of blooms that I can cut and bring indoors all summer long.

Go for it and have fun!