Welcome to Holland?
A question I get a lot when Im out looking at properties is when should I cut back my daffodils and tulips?. Along with that they tell me that they know you are supposed to tie your daffodil leaves into knots and leave them until they yellow, and so on.
The pat answer used to be that tulips wont acclimate to our zone and thought they do come back a second and a third year, they really are not worth saving as the blooms are much smaller. We basically told folks to rip out the bulbs and start over if they want a real burst of color. However, this is less true than it once was. We are noticing that there are many properties where tulips are coming back five, six, seven years now and looking just as good as they did the first year. True, not all the bulbs are coming back, but those that are seem to be acclimated.
Today, we leave tulips in the ground and once the leaves start to yellow, we cut them back to the ground. Really you dont even need to cut them, give the leaves a twist (not a pull) and they will come right off the bulb. Once leaves begin to yellow, they are no longer photo synthesizing and sometimes drain the bulb more than they help it, so removing them is easy since the bulb is ready to let go.
Daffodils on the other hand wont yellow right away. They will first flop to the ground indicating that the bulb is reducing support for the leaves since they are minimally recharging the bulb at this stage. However, wait a week to ten days from the time the daffodils go flat before trying to remove the leaves. Again, a good twist will usually release the leaves if the bulb is ready to let go. So what about all that knot tying you may well ask?
Daffodil flowers will develop seed pods, if you want the seed pods to germinate and produce more daffodils; you have to leave the yellowing collapsed leaves (and seed pods) which looks messy. Some clever gardener decided to tie them into knots which says , I am not a sloppy gardener, I am keeping these yellow nasty leaves for a reason. The other reason you might want to do this when ripening the seeds is because the leaves flop right on top of every other perennial struggling to reach the light through the daffodils, and bundling the leaves into a nice tight know gives other plants room to grow. If youre not keen on having your daffodils seed, then just twist or cut them off. In fact, a downside of allowing them to seed is less energy is stored in the bulb (because its going into the seed) and next years flowers will be smaller.