Rhododendron Fertilizer
Support deep green rhododendron foliage and healthy bud development for the next spring flower display. This fertilizer is made for acid-loving rhododendrons and can also fit into care for related azaleas.
Mix it into your normal watering routine as directed for consistent feeding through the active growing season.
Why You'll Love It
- Bloom Support Gentle feeding that supports the loaded spring flower trusses rhododendrons are grown for.
- Healthy Foliage Supports deep green leaves on acid-loving rhododendrons and azaleas.
- Steady Growth Feeds shrubs through the active growing season without pushing soft growth.
Made by growers
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Rhododendron fertilizer for deep green leaves and loaded spring flower trusses. Gentle feeding supports acid-loving rhododendrons and azaleas during the growth and bud-setting periods that shape the next bloom.
How to Use Rhododendron Fertilizer
| Method | Amount | How Often |
|---|---|---|
| Watering can (spring & summer) | 2 Tbs (30mL) per gallon of water | Apply every 1-2 weeks |
| Watering can (fall & winter) | Same dilution | Apply every 4 weeks |
| Hose end sprayer | Set dial to 1 oz (30mL) setting | Apply every 1-2 weeks in spring and summer |
| Leaf misting (optional) | 1 tsp per quart (32 oz) of water | Spray on leaves every 1-2 weeks |
Mix into your normal watering — no separate feeding routine needed.
What's Inside
A 3-3.6-5.1 ratio weighted toward bloom. Potassium leads at 5.1%, supporting the water regulation and sugar movement behind full flower trusses, and 3.6% phosphate feeds bud development and the fine, shallow root system rhododendrons keep near the soil surface. Nitrogen sits at 3%, all of it nitrate nitrogen — the form roots absorb directly, fast-acting with low burn risk — enough to keep the evergreen foliage dark and full without pushing soft leafy growth at the expense of next spring's buds.
Beyond NPK: sea kelp (Ascophyllum nodosum) for natural growth compounds, plus calcium at an unusually high 2.1% and 0.75% magnesium, with iron, manganese, zinc, copper, and boron. Iron and magnesium are the two rhododendrons run short of first — in soil that isn't acidic enough, both get locked up, and the shortage shows as yellowing leaves with green veins on new growth, then paler, sparser foliage overall.
Made For
Evergreen and deciduous rhododendrons — PJM, Catawba hybrids, Nova Zembla, Roseum Elegans, and compact Yakushimanum types — as foundation shrubs, woodland-edge plantings, and container specimens in dappled or bright indirect light.
Problems It Solves
- Yellowing leaves with green veins on new growth
- Few or no flower trusses in spring
- Sparse, leggy foliage instead of dense evergreen cover
- A newly planted rhododendron that has stalled instead of establishing
FAQs
How often should I feed rhododendrons?
Add 2 Tbs (30mL) per gallon of water and apply every 1-2 weeks in spring and summer, then drop to every 4 weeks in fall and winter. A hose end sprayer set to the 1 oz (30mL) setting covers larger foundation plantings, and you can optionally mist leaves with 1 tsp per quart every 1-2 weeks. Mix it into your normal watering.
Why isn't my rhododendron blooming?
The most common causes aren't nutritional: pruning after mid-summer removes the buds that were already set for next spring, deep shade limits bud formation, and a hard winter can kill buds outright. Prune only right after flowering and check the light first. Feeding supports bud set once timing and light are right — the phosphate and potassium in this ratio are weighted for exactly that.
Why are the leaves turning yellow with green veins?
That pattern is iron chlorosis, and it's the classic rhododendron complaint. It usually means the soil pH is too high — rhododendrons need acidic soil, and above roughly pH 6.5 iron gets chemically locked away from the roots. This formula supplies iron directly, which helps, but if your soil is alkaline, also work in a soil acidifier or plant in amended beds for a lasting fix.
Do rhododendrons need special acid fertilizer?
Rhododendrons need acidic soil more than they need a special fertilizer — pH is what controls whether roots can access iron and other nutrients. This formula supplies the bloom-weighted NPK plus the iron, magnesium, and manganese rhododendrons commonly run short of. If your soil pH is high, pair feeding with an acidifying amendment; fertilizer alone doesn't lower pH meaningfully.
When should I stop feeding for the year?
Shift to the every 4 weeks fall and winter schedule as growth slows — the label keeps a light feed going rather than a full stop. Avoid pushing the spring-summer schedule late into fall, since soft new growth started then is vulnerable to winter damage. Buds for next spring are already formed by late summer; the reduced schedule maintains the plant without forcing growth.
When will I see results?
All the nitrogen is nitrate nitrogen, absorbed directly by the roots, so it starts working with the first watering. Expect deeper green foliage within 2-3 weeks, with chlorotic leaves recovering as new growth comes in. Bloom results follow the plant's calendar: feeding this season builds the buds that open next spring, so the flower payoff shows in the following bloom cycle.