I need information on the best time to cut off the stems at the base
on 'Bulbs", that
 have finished flowering. I have been given different advice, on when
to do this. I understand that the bulbs continue to use the stems for
energy for the next growing season. Thank You

Hi tick: 

Thanks for the interesting question. 

From my researchm the answer to your question is basically that the
stems and leaves of bulb flowers that have already bloomed should be
left until they turn yellow. At that point, they should be cut back to
ground level. However, the flower heads should be cut off as soon as
they have finished flowering.


Sources: 

3441 - Care of Spring Bulbs after Blooming
URL: http://www.mobot.org/gardeninghelp/hortline/messages/3441.shtml
Quote: "Then, there is always the question of what to do with the
foliage. The temptation for many is to bunch the leaves with a rubber
band or string into a nice tidy bundle. Alternatively, some people
will cut the foliage back to the ground. Both of these practices will
reduce bulb development and flower formation next season. Instead, the
foliage should be allowed to sprawl out to collect as much sunlight as
possible. Daffodils are sensitive to premature leaf removal and their
should be a least 4 to 6 leaves per bunch to support bulb growth. The
same follows for tulips, however, they are less sensitive. So as long
as you leave the bottom two leaves intact, new bulbs produced will
develop to normal size. So, be patient to cut the foliage back until
signs of leaf yellowing. Generally, tulips can be cut back in mid-June
while daffodils often take a month longer. At this time cut the leaves
back to the ground level and compost the leaf material."

Care
URL: http://www.tulipworld.com/tulip.asp?contentloc=/info/bulbcare/care.shtml
Quote: "After flowers have finished, cut off the spent flower stems
but do not cut back the foliage. If you cut off the leaves before they
died down naturally, the bulb will not have the reserves to grow and
flower the following season."

Top FAQs about Planting Bulbs 
URL: http://www.ohio.com/mld/philly/living/home/2749757.htm
Quote: "Last year I planted a variety of bulbs. Can I cut the flowers
and bring them inside without weakening the bulbs for next year?
By all means cut the flowers and stems to take indoors, but be sure to
leave the foliage. The leaves manufacture food for the bulb so it can
develop next year's bloom. Allow the leaves to die down naturally,
then gently pull them or cut them off at ground level."

Plant Spring Bulbs Now!
URL: http://ourgardengang.tripod.com/Bulbs.htm 
Quote: "Remember that except for the flower stem itself, bulb foliage
should not be cut back, but should be left to die back naturally or
'ripen' after blooming.  This provides the bulb with nourishment to
bloom again next year"


I hope this information helps with your research.          
                                   
If you need any clarification of the information I have provided,
please ask using the clarification feature and provide me with
additional details as to what you are looking for. As well, please
allow me to provide you with clarification(s) *before* you rate this
answer.
                                   
Thank you.                                    
                                   
websearcher-ga                                    
                                                     
            
Search Strategy (on Google):       

"cut back" bulbs
"cut back" daffodils tulips crocuses