I use glyphosate(Round Up)but only when I absolutely have to. April

Triclopyr is commonly used for control of woody plants, including poison ivy, as it works better than many other kinds of herbicides for that purpose. It is a selective herbicide unlike Roundup, which means it will not affect grasses. This can be a desirable trait depending on the site. Along with Roundup, it is one of the more common herbicides used to control non-native invasive plants during habitat restoration. There are two forms available, an ester form, and an amine form. The ester is much more likely to volatilize and move when applied during warm or hot conditions, and its use is typically reserved for colder times of year. The ester form does penetrate plant tissues more readily though. The amine form is a better choice in warmer conditions. The link more fully explains the material.

Here is a link that might be useful: Nature Conservancy - triclopyr

Thanks for the info, JayK!

Small courtyard grass killed by roots from two crepe myrtles & sago palms. Dug out two inches of dirt to replace with crushed limestone (the pretty red kind),several 16" stepping stones & pavers around birdbath. Courtyard is a mass of roots from trees & shrubs. Will cut roots at edge of flowerbed so as not to kill trees & shrubs. What is most effective method of applying Triclopyr to kill roots to prevent problems down the road? Is there something more effective than Triclopyr??

I have no personal knowledge or experience but have read that triclopyr is not as effective when applied to roots. It's absorbed and works better through foliage or fresh stump cuts. "Triclopyr is most effective when applied to actively growing plants." (http://www.hort.uconn.edu/cipwg/art_pubs/GUIDE/consideration.htm)
and
"Triclopyr is absorbed by leaves and roots and is moved throughout the
plant. Lab experiments indicate that foliar uptake is fast with 90% of applied TBEE penetrating vegetation in about 12 hours (McCall and Gavit et al., 1986). Triclopyr can damage plants due to root uptake BUT DOES NOT WORK EFFECTIVELY THAT WAY (Newton et al., 1990)." (www.cdpr.ca.gov/docs/emon/pubs/fatememo/triclopyr.pdf)

You also need to be careful what else is in the formulation. Maybe your state extension agents could give you more information.