Question
QUESTION: i've had this plant 20 years since i've been in this house  it got about 8" tall and bushy  every year beutiful yellow flower  this year it was way more abundant with flowers than previous years  but now within the past month it turned brown and as if it died   is there a life span or what  we would appreciated some input   we just today trimmed it back  but i  stopped just incase it went into some state ?????   thank u

ANSWER: Hi Ed,
Thank you for your question.  Can you tell me your approximate location?  There is an insect that attacks the yellow sweet broom.  It could be that you have an infestation of the genista caterpillar which can be controlled with Bt (Bacillus thuringiensis) a natural insecticide which is harmless to humans and animals and birds.  Look carefully on the plant for worms.  Here is a link for some pics of the pest.  Let me know where you are and what you find.  I hope this helps.
Tom

http://hortipm.tamu.edu/pestprofiles/chewing/genista/genista.html

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QUESTION: location is sacramento,ca      but it flowered like never before then it like turned totally brown   the inside was still green but hard  never saw any worms/caterpillars   it was a beautiful bush   the trunk is approx 4 to 5 inches  we cut the branches back to the main ones  dont want to cut/dig it up if it can be saved    thank u for repling

Answer
Hi Ed,
Thanx for the additional information.  There are some varieties of sweet broom the State of California has asked not to be propagated.  I find that a lot of people in California don't know this.  The genista caterpillar was brought in to help control the invasiveness of some sweet brooms.  Contact your local County Extension agent for more local information.

Here's a link to the Sacramento County Extension of the University of California-Davis.

http://cesacramento.ucdavis.edu/

I think you did the right thing to cut the shrub back like you did.  You may want to take a sample in to the County Extension Horticultural Agent.  Remove all the dead growth, leaves, etc. and burn it.  Side dress the plant with well-composted cow manure and give it some water.  Hopefully, it will have come out of whatever was ailing it.

Here is some more info on brooms in California.

http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2009/04/10/HO6B166O1P.DTL

Check at the base of the shrub to see if there is any shriveling or color change as this could indicate a root rot problem brought on by fungus otherwise it could be just an airborne fungus problem.  If it's an airborne fungus, you've removed what needs to be removed.  If it's root rot sometimes you can dig around the plant, remove the damaged roots and then replace the infected soil with new soil.  I hope this helps.
Tom