Warden Leveling

Bare minimums for a warden are 6 blades for taunt (usually 10 for side snare), 12 regrowth for endurance cost reduction (at 22 regrowth for the second reduction, one can permasprint with end3 pots and without the self end chant, LW, or tireless), and 45 nurture for the 6s bladeturn pulse. (Because of custom immunity to bladeturn dynamics, running multiple wardens and stacking their BT chants requires split-second timing and isn't practical.)

For leveling, it's an early goal to get 6 blades, 12 regrowth, and nurture to level, but in what order you do these is a personal taste. If you do nurture first, you get a damage-add chant at 5, 9, and 14, which can keep your damage output reasonable until you can get your blade spec up. If you're not using styles in combat, then the end reduction isn't a thing for a while. If you run the level 2 regrowth end4 chant, you can use styles with some impunity, but you'll have to twist it with the damage add chant, and casting the chants do themselves take some endurance and can wipe out the gains from the end4 chant.

I've done these in multiple orders, and I don't have a feel for which is best. I do expect in any case to have the basics down by level 15-20. After that, it's more regrowth for better heals or more blades for better damage.

Above 45 nurture has one more damage-add chant at 46, then more group resists at 48 and 49; these could be vital or trivial to you.

The selfish warden:
22 regrowth (or 12, with more blades / parry)
46 nurture
39 blades
14 parry

The helpful warden:
43 regrowth
49 nurture
10 blades
0 parry