How can I get rid of the spiders on my californian lilac?

Question

I have loads of spiders having their nests and webs on ly little californian lilac. In spring when I got it, it was full of flowers, but now most of the leavees have either fallen off or are yellow, I have only 3 fruit bodies on it where in the past there were flowers and the rest is full with small spiders and their webs.
Can anyone help please? Thank you!

Answer 1

it is not the spider that are damaging the plant. Spiders are predators so they are probably there dining off the insects damaging your plant. So before you spray check for other possible causes for the damage. Examine the underside of leaves, stems, and fallen material for evidence.

Once you know what is the specific problem treat it with the recommended control method and the spiders will leave for better hunting grounds. Right now they may be protecting your plant.
Ceanothus suffer several pests.
Ceanothus stem gall moth that causes spindle shaped swellings (galls). Infestation may cause serious dieback. These need to be cut out and destroyed.
http://oregonstate.edu/Dept/nurspest/Ceanothus_stem_gall_moth.htm
www.ipm.ucdavis.edu/PMG/GARDEN/PLANTS/INVERT/ceanothusgallmth.html

Ceanothus tingids (lace bug).
http://bugguide.net/node/view/57389/bgpage
http://pubs.caes.uga.edu/caespubs/pubcd/b1102-w.html
Ceanothus is susceptible to oystershell scale.
http://www.ento.psu.edu/extension/factsheets/oystershellScale.htm
http://www.ext.vt.edu/departments/entomology/factsheets/oystersc.html

Answer 2

Spray with a dishsoap & water solution every other day for a week to start then about once a week. But first, use a duster or soft brush to rid the existing spiders/webs.
I use it on my plants and window screens, too!