Once again, I find myself suggesting you tell the EC they can do this the easy way, or the hard way.
The easy way is that they approve a budget for the gardening works and allow you to do the work. You will supply them with receipts for any purchases and you will sign a document indemnifying them for any OHS issues.
The hard way is that you will apply to the CTTT for an order against them to force them to maintain the common property as is their legal duty under section 62 of the Act:
62 What are the duties of an owners corporation to maintain and repair property?
(1) An owners corporation must properly maintain and keep in a state of good and serviceable repair the common property and any personal property vested in the owners corporation.
(2) An owners corporation must renew or replace any fixtures or fittings comprised in the common property and any personal property vested in the owners corporation.
(3) This clause does not apply to a particular item of property if the owners corporation determines by special resolution that:
(a) it is inappropriate to maintain, renew, replace or repair the property, and
(b) its decision will not affect the safety of any building, structure or common property in the strata scheme or detract from the appearance of any property in the strata scheme.
Note section 3B which spells out that the appearance of common property is a significant issue in the obligation to maintain and repair and says that the owners Corp can’t decide not to do work if that means the appearance is negatively affected.
Realistically, I would offer lots of carrot before I reached for the stick. But I’d pull it out the moment I saw any signs that your very generous offer was heading towards the ‘too-hard” basket. A little gentle lobbying before you present your proposal – make the EC members feel important – will go a long way.