Breloom
- Very High Attack stat of 130
- Average speed of 70.
- As we know that grass is Special in Gen-3, Breloom's grass stab doesn't hit hard.
- It doesn't do anything that Blaziken can't do (Shares Fighting typing with Blaziken).
Cacturne
- Good attacking stats, each of 115
- Does good against Phoebe.
- Very slow
- Very Frail
- Strongest stab's base power is just 60.
As you can see, grass types are either horrendous or don't suit to Blaziken team, except maybe Vileplume.
One grass Pokemon that's a lot better than Cacturne (and doesn't share a type with Blaziken) is Vileplume, which gets sleep powder and sludge bomb.
commented 1 hour ago by sumwun
You can also use it (Sleep Powder helps your team greatly), but I would give you a better alternative, mainly for Flying types Blaziken is weak to.
Grass typing covers Water, Rock & Ground right? So I would recommend you a good Electric type and a Water type.
Manectric has good attacking stats, available early, is fast, useful against Winona, Juan and Wallace, and is able to counter water types, but it has poor movepool.
Manectric
Ability: Static / Lightning Rod
- Thunderbolt
- Thunder Wave
- Bite / Crunch (if you can acquire)
- Strength / anything else
Tentacruel is available as early as Dewford town, is fast, is a great surfer, useful against Flannery, Winona (Ice Beam) and Drake (Ice Beam again), and is able to counter rock and ground types.
Tentacruel
Ability: Liquid Ooze / Clear Body
- Surf
- Waterfall
- Dive
- Ice Beam
Hope this helps :)