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Pelargonium or hardy geranium: which plant to feed

Updated: October 2026

The packet says geranium, and you are not sure whether that means the red flowers in the window box or the cranesbill along the path. Pelargonium or geranium feed is a naming question before it is a shopping question. In UK shops, geranium usually means a pelargonium. The Royal Horticultural Society uses Geranium for hardy cranesbills and Pelargonium for the tender plants. A fertiliser listing built for the tender plant is the wrong default for a border cranesbill on ordinary soil. The [geranium fertiliser comparison](/hub/fertiliser-soil-and-bark-mulch/geranium-fertiliser) is the shelf for the pelargonium job. A qualifying purchase can earn a commission at no extra cost to you.

The packet says geranium, and you are not sure whether that means the red flowers in the window box or the cranesbill along the path. Pelargonium or geranium feed is a naming question before it is a shopping question.

Our top picks

Cultivers Cultivers organic geranium and flowering plant fertiliser 250 g

Best overall

Cultivers Cultivers organic geranium and flowering plant fertiliser 250 g
10.0/10about £11.62
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Fertiligène Fertiligène Osmocote Max geranium fertiliser 700 g

Alternative

Fertiligène Fertiligène Osmocote Max geranium fertiliser 700 g
9.4/10about £23.00
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Cultivers Cultivers organic geranium and flowering plant fertiliser 1 kg

Best value

Cultivers Cultivers organic geranium and flowering plant fertiliser 1 kg
8.8/10about £15.53
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On this page
  1. 1.Two plants, one shop name
  2. 2.What hardy geraniums need
  3. 3.What pelargoniums need instead
  4. 4.The exception that is still not a zonal geranium

Two plants, one shop name

A bedding geranium will not take a British frost. Ivy-leaved types trail, and they are still pelargoniums. A hardy geranium is a border cranesbill with a different winter. The RHS states the mix-up: people say geranium for Pelargonium, and Geranium is another genus. If you bring the plant in, or lose it to frost, you are feeding a pelargonium. If it comes back in the border without a fleece, you are looking at a cranesbill. In much of the UK, tender plants go out around the end of May, and in Scotland often early to mid June. Shop titles that say geranium do not mean a border cranesbill needs the same bag.

What hardy geraniums need

On most garden soils the RHS says feeding hardy geraniums is not generally necessary. Feed only if poor, pale growth is not simply drought, shade, or a clump that wants dividing. Gardeners' World describes the same plant: mulch, and do not buy a special fertiliser as routine care. A March controlled-release habit in other articles is not the RHS position. An 8-1-5 pack pushes soft leaf on a cranesbill that is already flowering. The 20 kg listing is a poor match: form unstated, ratio disputed, mass absurd for one clump. A cranesbill in a pot can take a modest general liquid if growth is poor. That is not a high-nitrogen granule bought because the packet says geranium.
Cultivers Cultivers organic geranium and flowering plant fertiliser 250 g

Testsieger

Cultivers Cultivers organic geranium and flowering plant fertiliser 250 g
10.0/10about £11.62
View offer

What pelargoniums need instead

Most pelargoniums flower best with some potassium-rich fertiliser. The RHS growing guide says a balanced liquid every 10 to 14 days in spring, then a high-potassium feed such as tomato feed every fortnight once flowers form. Monthly only if you keep the plant warm and still growing. Stop if you dry it off. The steps sit on how to feed geraniums. Ivy-leaved plants sold as ivy geraniums stay in this group. The 4-1-7 liquids lean toward potassium. The 8-1-5 packs print more nitrogen. Neither belongs on a healthy border cranesbill as a habit. The Osmocote tub is a once-in-the-season granule claim, with no NPK in the product data.

The exception that is still not a zonal geranium

Geranium maderense and Geranium palmatum break the hardy-so-do-not-feed shortcut, and they are still not zonal pelargoniums. The RHS says container-grown plants of these tender species can take a general liquid, seaweed is the example, from spring to late summer. They are large plants, not the red bedding flower in a 12 cm pot. An 8-1-5 flowering-plant pack is not their default. Use a general liquid at the label rate if growth justifies it. Do not copy a hanging-basket schedule onto them in the ground. The bedding plant is the one the Cultivers and Osmocote titles are written for. A healthy cranesbill in ordinary soil is not the customer.

Common questions

Are window-box geraniums the same as hardy geraniums?
No. Window-box and basket plants sold as geraniums are pelargoniums. They are tender, and they are the plants these fertiliser titles are aimed at. Hardy geraniums are cranesbills, a different genus, usually left in the border over winter. The shared English name is the reason the wrong bag gets bought.
Do cranesbills need this fertiliser?
Usually not. The RHS says feeding is not generally necessary on most garden soils. Mulch is the routine care Gardeners' World describes. Feed only if a deficiency shows. A special 8-1-5 geranium pack is an impulse buy for a plant that is already doing the job in decent ground.
What if the cranesbill is in a pot?
Compost in a pot runs out faster than border soil, so a modest general feed can make sense if growth is poor. That is not an invitation to use a high-nitrogen pelargonium granule by habit. If the cranesbill is actually a tender pelargonium, use the pelargonium calendar instead.
What are G. maderense and G. palmatum?
They are tender Geranium species, not zonal pelargoniums and not typical hardy cranesbills. In containers the RHS suggests a general liquid fertiliser, such as seaweed, from spring to late summer. They are large plants. A bedding geranium bottle is not their default feed.
Will a high-nitrogen granule help a cranesbill flower?
Not as a routine. Extra nitrogen favours leaf. The RHS does not recommend a flowering-plant granule for hardy geraniums on most soils. If flowering is poor, look at light, division, and water before you add an 8-1-5 pack meant for pelargoniums and other bedding.
Which page do I read if I do have pelargoniums?
Use the buying guide for form and pack size, the pots page if they are in baskets or window boxes, and the how-to page for the spring and summer calendar. The comparison lists the eight ASINs with prices. This page only stops the wrong plant from being fed.
Should I feed because the packet says geranium?
Only after you know which plant you have. The packet uses the shop name, which in Britain usually means pelargonium. A hardy cranesbill in ordinary soil does not need that packet because the word matches. Read the plant, then the label, then decide whether any feed belongs there at all.

Related pages

Geranium fertiliser buying guide

Geranium fertiliser for pots and baskets

Geranium fertiliser

Best geranium fertiliser for pots, once or baskets

How to feed geraniums in spring, summer and winter

Sources

Public UK sources from the research digest, used for this page in October 2026. Prices, stars and review counts are from the eight amazon.co.uk listings captured on 19 October 2026. Organic, vegan and pet-safety lines are listing claims. The one-year granule line is the listing's claim, not a laboratory result. French, Spanish and Belgian reviews are not British comments.

  1. RHS, How to grow pelargoniums (retrieved 19 October 2026)
  2. RHS, How to grow geraniums (retrieved 19 October 2026)
  3. RHS, How to feed plants (retrieved 19 October 2026)
  4. RHS, Fertiliser labels explained (retrieved 19 October 2026)
  5. GOV.UK, Manufacturing and marketing fertilisers (retrieved 19 October 2026)
  6. legislation.gov.uk, Regulation (EC) No 2003/2003 Title I (retrieved 19 October 2026)
  7. RHS, Storing and disposing of chemicals safely (retrieved 19 October 2026)
  8. amazon.co.uk listings for the eight compared packs (retrieved 19 October 2026)