Nothing ruins the clean line of a privacy hedge faster than yellowing foliage or bare brown patches at the base of your arborvitae. These evergreens look tough, but they’re heavy feeders that strip nitrogen and potassium from the soil within a few seasons. Without targeted feeding, even a mature Emerald Green can go from lush to lackluster in one dry summer.
I’m Mohammad Maruf — the founder and writer behind Gardening Beyond. I’ve spent years dissecting the NPK ratios, release mechanisms, and chelated micronutrient profiles that actually move the needle for arborvitae, cross-referencing manufacturer claims against long-term owner experiences.
Choosing the right food for arborvitaes means understanding whether a slow-release spike or a fast-acting liquid better suits your soil type, watering schedule, and the specific growth stage of your hedge.
How To Choose The Best Food For Arborvitaes
Arborvitae are shallow-rooted evergreens that respond strongly to the correct balance of nitrogen for foliage, potassium for root and disease resistance, and micronutrients like magnesium that keep needles from yellowing between the veins. A poor match of release type or nutrient ratio can cause tip burn, salt damage, or nutrient lockout.
NPK Ratio: Nitrogen Comes First
Look for a first number (nitrogen) between 10 and 16. Arborvitae use nitrogen heavily to manufacture chlorophyll for their scale-like leaves. Phosphorus should be the middle digit, kept moderate — 3 to 6 — because arborvitae aren’t heavy bloomers or fruiters. Potassium (the third number) should match or exceed nitrogen for winter hardiness and root vigor.
Spikes vs. Liquids: Release Speed Matters
Spikes are pre-measured and release nutrients over 60–90 days through microbial breakdown. They’re ideal for established hedges where you want a single spring application. Liquids are absorbed through roots within hours, making them better for correcting a visible deficiency mid-season or feeding newly planted arborvitae during their first two growing years.
Micronutrients: Magnesium and Iron
Magnesium prevents interveinal chlorosis — yellowing between the veins — a common arborvitae issue in acidic or sandy soils. Iron helps maintain deep green color. A good arborvitae food should list chelated iron or magnesium sulfate (Epsom salt equivalent) in its guaranteed analysis, especially if your soil pH is above 6.5.
Quick Comparison
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| Model | Category | Best For | Key Spec | Amazon |
|---|---|---|---|---|
| Jobe’s 16-4-4 Spikes (30 Count) | Mid-Range | All-season feeding of mature hedges | 16-4-4 NPK, 30 spikes | Amazon |
| The Old Farmer’s Almanac 10-4-10 Spikes | Mid-Range | Balanced feeding with magnesium boost | 10-4-10 NPK, 6% magnesium | Amazon |
| TPS Nutrients Arborvitae Liquid | Mid-Range | Quick correction of yellowing foliage | 32 oz liquid concentrate | Amazon |
| Jobe’s 13-3-4 Evergreen Spikes | Budget-Friendly | Simple spike feeding for young evergreens | 13-3-4 NPK, 15 spikes | Amazon |
| Great Big Plants Roses & Flowers Booster | Budget-Friendly | Soil conditioning and micronutrient supplement | 32 oz, organic compost extract | Amazon |
In‑Depth Reviews
1. Jobe’s Tree Fertilizer Spikes 16-4-4 (30 Count)
This package delivers thirty spikes — a two-year supply for most mature hedge rows — with a high-nitrogen 16-4-4 ratio that directly targets the dense green foliage arborvitae are prized for. The spikes are formulated for all deciduous trees and shrubs, but the elevated nitrogen and even potassium (4) make it especially suitable for evergreens that need sustained color through late summer.
Each spike feeds continuously below the surface for the entire growing season, eliminating the runoff risk and root-zone variability common with granular top-dressing. Owners consistently note that their arborvitae filled in gaps at the interior of the hedge within one full season after switching from a balanced 10-10-10 fertilizer.
The 8.27-pound total weight means the spikes are solid and well compressed — they won’t crumble during driving or when hammered into firm clay soil. The 16-4-4 ratio is high enough to deliver visible results but not so aggressive that it burns roots when placed at the recommended drip line distance.
What works
- High nitrogen for rapid green-up and dense foliage.
- Large count per package covers extensive hedges.
- Zero mixing, measuring, or runoff concerns.
What doesn’t
- Not ideal for correcting acute mid-season deficiencies — spikes take weeks to fully activate.
- Target species listed is broad (all trees/shrubs) rather than arborvitae-specific.
2. The Old Farmer’s Almanac Evergreen Spikes 10-4-10 (12 Spikes)
This spike stands out because of the 6% magnesium inclusion — a specific micronutrient that arborvitae in neutral to alkaline soils often lack. The 10-4-10 ratio is more conservative on nitrogen than Jobe’s 16-4-4, but the elevated potassium matches the nitrogen pound-for-pound, providing superior root and cold-weather resilience for hedges in northern zones.
The patented TruSpike construction is noticeably denser than typical crumbly spikes. You can drive it into heavy clay or compacted soil along a driveway without the spike splitting or pulverizing. The pre-measured format means two applications per year — early spring and late fall — is sufficient for most established arborvitae, with an optional summer boost during drought or after shearing.
Because the NPK is moderate rather than aggressive, this is a safer choice for younger arborvitae where root burn is a real risk. Users working with Green Giant or Emerald Green varieties report even, natural green color without the excessive soft growth that high-nitrogen spikes can trigger before winter dormancy.
What works
- Magnesium directly addresses yellowing between leaf veins on older foliage.
- Physically durable spikes withstand rocky or compacted soil.
- Balanced ratio reduces burn risk for young or stressed trees.
What doesn’t
- Only 12 spikes per pack — higher per-spike cost than bulk alternatives.
- Lower nitrogen may not satisfy owners wanting rapid visual fill-in on thin hedges.
3. TPS Nutrients Arborvitae Liquid Fertilizer, 32 oz
This is the only product in the lineup explicitly labeled for arborvitae, and that specificity shows in its formulation. The liquid concentrate targets root uptake within hours, making it the go-to choice when you spot pale new growth on your Emerald Greens in mid-July and need to correct a nitrogen or iron deficiency before the foliage yellows permanently.
The mixing rate is two tablespoons per gallon of water, giving you 16 gallons of ready-to-use feed from one 32-ounce bottle — enough to treat a long privacy hedge in a single watering session. Because it’s liquid, you can target the root zone directly without worrying about spike placement errors near shallow roots, which is a common issue with arborvitae planted close together.
Owners report visible greening within 5–7 days after application, especially on arborvitae that had been showing tip chlorosis. The fast absorption also means you can adjust feeding frequency based on weather — more frequent in rainy seasons when nitrogen leaches, less during dry spells. It’s made in the USA and comes with a measurable dosing system, unlike many generic liquid feeds.
What works
- Fast-acting liquid corrects deficiencies within a week.
- Formulated specifically for arborvitae, not just generic evergreens.
- High dilution ratio provides excellent coverage per bottle.
What doesn’t
- Requires measuring and mixing — less convenient than hammer-in spikes.
- Must be reapplied every 4–6 weeks for continuous feeding throughout the season.
4. Jobe’s 01313 Evergreen Fertilizer Spikes 13-3-4 (15 Count)
The 13-3-4 ratio is a solid entry point for arborvitae owners who want the convenience of spikes at a lower upfront cost. The nitrogen is adequate to maintain existing green color in established plants, and the slow-release mechanism feeds for up to 90 days, which means two applications per season — spring and late summer — cover the entire growing window without additional effort.
These spikes are purpose-marketed for evergreens, and the 15-count package aligns well with a small hedge or a handful of individual specimens. The low phosphorus (3) matches the needs of arborvitae, which don’t divert energy into flowering, but the potassium (4) is on the lower side compared to the Old Farmer’s Almanac option, making it less suited for winter stress protection in cold climates.
In practice, owners find them easy to drive into moist soil, though the spikes are slightly more brittle than the TruSpike design. They work best when the ground is damp after rain or watering, reducing the chance of the spike snapping before it reaches the root zone. As a seasonal-maintenance tool for healthy hedges, this is a reliable, no-fuss choice.
What works
- Good value per spike for covering multiple trees on a budget.
- Slow-release formulation prevents nutrient runoff and root burn.
- Easy to store and apply without measuring or mixing.
What doesn’t
- Potassium level is moderate — not ideal for heavy-winter zones.
- Spikes are somewhat brittle; dry soil increases breakage risk during installation.
5. Great Big Plants Roses & Flowers Liquid Booster, 32 oz
At first glance, a rose-and-flower booster seems out of place for arborvitae, but this product’s strength lies in soil biology rather than raw NPK numbers. It’s a proprietary compost extract loaded with over 70 chelated trace minerals, bioavailable humic acids, and seaweed — nutrients that unlock locked-up soil reserves and improve the efficiency of any base fertilizer you’re already using.
For arborvitae planted in degraded fill soil, compacted subdivisions, or nutrient-poor sandy loam, this liquid re-establishes the microbial bridge between roots and soil particles. The immediate flow to the root zone helps roots absorb more of whatever spike or granular feed is already present, essentially amplifying your main feeding program without adding more synthetic salt.
Because it’s USDA-listed as an Organic Input Material, it’s the only product here that qualifies for certified-organic landscapes. The mix rate of 1 tablespoon per pint of water is potent, so a 32-ounce bottle goes further than its volume suggests. Owners who rotate this with a high-nitrogen spike report healthier root systems and fewer instances of mid-summer yellowing than with spikes alone.
What works
- Dramatically improves nutrient uptake of existing fertilizers.
- Organic Input Material registration suits certified-organic gardeners.
- Chelated trace minerals address hidden micronutrient deficiencies that NPK alone misses.
What doesn’t
- Low direct NPK — cannot replace a primary nitrogen source for hungry arborvitae.
- Formulated for roses/flowers, so labeled use case doesn’t match arborvitae directly.
Hardware & Specs Guide
NPK Ratio
The three-number sequence on the label corresponds to nitrogen, phosphorus, and potassium by weight. For arborvitae, the first number (nitrogen) is the primary driver of green foliage density. Spikes with a ratio near 16-4-4 or 10-4-10 match the plant’s natural demand pattern, while balanced ratios like 13-3-4 work for maintenance feeding.
Slow-Release Mechanism
Spike fertilizers rely on soil moisture and microbial activity to slowly break down the compressed nutrients. This process typically lasts 60-90 days per application. Liquids offer no slow-release benefit — they are absorbed within hours but require repeat applications every 4-6 weeks for consistent feeding throughout the growing season.
FAQ
How many spikes should I use per arborvitae tree?
Can I use a general-purpose 10-10-10 fertilizer on arborvitae?
When is the best time of year to feed arborvitae?
My arborvitae has yellow tips. Will fertilizer fix this?
Final Thoughts: The Verdict
For most gardeners, the food for arborvitaes winner is the Jobe’s 16-4-4 Tree Fertilizer Spikes (30 Count) because the high-nitrogen slow-release formula sustains dense, dark green foliage through the entire growing season with just two applications per year. If you want a balanced spike with a magnesium boost for winter hardiness, grab the The Old Farmer’s Almanac 10-4-10 Spikes. And for correcting mid-season yellowing or feeding young transplants, nothing beats the fast-acting precision of the TPS Nutrients Arborvitae Liquid.