Time for something where we can actually debate about the LA again!
Woodling is basically 'Generic Plant Creature: the template', but that isn't necessarily bad. Interestingly enough (and, I must admit, not something I noticed the first time I read it), it specifically doesn't actually change the recipient's type even though it does give plant traits.
Other quickly enumerated bonuses are +7 natural armor, a weak (1d6 for medium creatures) slam attack, DR 5/slashing, low-light vision, +4 hide and move silently in natural environments, and fire vulnerability.
The final trait, and the one that prevents woodlings from being an easy +1, is the wisdom-based SLAs. They come in the familiar package where HD determines how many you get, and are either plant-related (Entangle, Speak With Plants) or summon-related (Summon Nature's Ally). All spells are gotten a bit after the point where actual casters would've obtained them. Of note is that they're generally only 1/day.
Do those SLAs cause the LA to raise to +2? I'm not sure: they're spread out over many levels, and by the time the highest ones are obtained the lower ones are basically irrelevant. In addition, SLA-less woodling is pretty weak for a +1 template, or at least not top-tier, which means that the SLAs are much less likely to tip it over the edge.
In the end, and comparing similar templates like shadow-walker, I'll go ahead and assign +1 LA here for now. Do discuss.