Expert: Kenneth Joergensen - 6/18/2004

Question
Is it necessary to mulch daffodils or will they do just as well without mulch?  These daffodils were planted three years ago and only recently was a mulch type (low quality -  a tree company donated the ground up trees for this project) used and we are considering removing it.

Answer
You don't need mulch on spring flowering bulbs and often it can actually interfer with the function.

Spring flowering bulbs need a consistent cold period of 15-18 weeks. In mild climates, adding a mulch in summer and leaving it can keep the soil warm through the early part of winter which limits the cooling period. If too short, the flowers wont bloom.

On the other hand, if the mulch is added after the ground freezes in winter, the soil will stay colder compared to unmulched ground and that could then ensure proper cooling.

So, if you are located in a mild climate, the best way is to apply a mulch, but only to do this after the ground has frozen.

If you live in a colder zone, mulch or not won't make a difference. the temperatures will be cold enough for the bulbs to accomplish the vernalization period. However, if there is no mulch on the ground in early spring the bulbs usually come up earlier than if covered by mulch. This is because the early spring sun will warm the soil faster without mulch, whereas a mulch covered ground will stay frozen for a longer period of time.

In short: unless you are in a very mild climate, you dont need mulch, and no mulch actually gives you faster flowering in spring. If you are in a southern gardening zone and have problems with vernalization period not being long enough for flowering, then adding a mulch after the ground freeze in winter is recommended.