Neutrog Kahoona, what it is and when to use it

March 28, 2025

Kahoona is Neutrog's organic based fertiliser for the acid loving shrubs, so azaleas, camellias, rhododendrons and gardenias, and the reason that group gets its own bag comes down to soil pH rather than to anything exotic about the plants themselves.

Why acid loving plants need a different product

Those shrubs come from soils on the acid side, and pH decides how much of each nutrient a plant can actually take up out of the ground. Iron is the one that matters here. As soil pH climbs towards neutral and past it, iron gets locked up in a form the plant can't use, and you end up with a plant sitting in soil that has plenty of iron in it and still going hungry.

The symptom is very recognisable once you know it. New leaves go pale yellow while the veins stay green, so the leaf looks like a road map. That's iron chlorosis, and it's the classic sign that an azalea or a gardenia is in soil that's too alkaline for it. Feeding it more of an ordinary fertiliser does not fix that, because the problem was never how much was in the ground.

What Kahoona is doing about it

It's a pelletised organic based feed formulated for that group of plants, so the nutrient balance suits them and it isn't working against the soil conditions they want. Being organic based, it breaks down slowly and puts organic matter into the soil while it goes, which is the part that actually helps a shrub long term.

When to feed them

The timing rule for azaleas and camellias is straightforward and most people get it wrong. Feed after flowering, not during, because that's when the plant is putting on the growth that carries next season's buds. A second lighter feed later in the growing season is plenty. Feeding hard while a plant is in full flower tends to shorten the display rather than extend it.

Things to keep away from them

Garden lime and dolomite. Those raise pH, which is the opposite of what these plants want, so keep them for the vegetable patch.
Wood ash, for the same reason. It's alkaline and it will undo what you're trying to do.
Heavy handed general fertiliser. These are shallow rooted shrubs and they burn more easily than most.
Digging around the base. The roots sit close to the surface, so mulch rather than cultivate, and keep the mulch off the stem itself.
Letting them dry right out. Shallow roots mean they feel a dry spell early, and a stressed shrub drops buds before it drops anything else.

If the leaves are yellow, test before you buy

A pH kit costs very little and it answers the question. If the pH is where it should be then the yellowing is something else, most often waterlogging or a plant sitting in the wrong spot, and no amount of fertiliser is going to help. If the pH has crept up, that's a soil job rather than a feeding job, and it's worth sorting before you spend anything else.

Shop related products

Kahoona 1.5kg Bucket. The Neutrog feed for azaleas, camellias, rhododendrons and gardenias.
Manutec Azalea & Camellia Fertiliser 2.5kg. The other option on the shelf for the same group of plants.
Manutec Soil pH Test Kit. The one that tells you whether pH is your problem before you buy anything else.
Brunnings Peat Moss 5L. Useful in the planting hole for an acid lover, and it holds moisture around shallow roots.

Did you know we also keep an azalea and camellia planting mix in the shop for anything going into a pot, and iron sulphate for correcting a soil that has drifted alkaline, and neither is listed on the website, so give us a ring on (08) 8536 4333 to check what's on the shelf.

The fertiliser range and the pH kits are both in our garden centre, and if you bring in a photo of the yellow leaves we can usually tell you straight away whether it's pH or something else.