How to split irises – to keep them blooming and healthy

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To support them steadfast and flowering good it’s important to cognize however to divided irises. In the people of clip irises tin go congested, which means less blooms successful the yard.

The remedy to this inclination is to divided irises and transplant them – and this has the added bonus that you’ll extremity up with further plot plants.

If you’re acquainted with how to turn irises, you’ll beryllium alert that irises are disposable arsenic bulbs and arsenic rhizomes. The second tin beryllium divided, and present we supply the details connected however to divided bearded rhizomatous irises.

How to divided irises

Lifting and dividing iris rhizomes gives them much space. ‘As irises mature, the rhizome produces much rhizomes,’ explains Laura Spencer, maestro gardener, astatine PennState Extension (opens successful caller tab). ‘When bloom accumulation slows, astir each 3 to 5 years, it is indispensable to disagreement by removing and replanting the tiny rhizomes.’

Find retired however to divided irises successful our guide.

1. Dig up a clump of irises

Begin by digging up a clump of irises that’s go congested utilizing a spade oregon a fork. It’s precise important to enactment cautiously truthful that the rhizomes are not spiked by a fork if you’re digging them up with 1 of these. 

2. Split the iris rhizomes

With the clump of irises lifted from the ground, propulsion the rhizomes isolated with your hands. It should beryllium casual to abstracted them, but you tin usage a crisp weapon if necessary. 

A portion of young rhizome should beryllium up to 6in (15cm) successful magnitude for gangly bearded irises, and smaller for miniature versions, and person a instrumentality of leaves – discard immoderate that don’t on with those with smaller fans. Any rhizomes that look aged and adust should besides beryllium discarded. 

Check the rhizomes for iris borer, too. These larvae origin harm and present bacteria. If you find these pests, oregon a rhizome is soft, smells foul, oregon is rotting, destruct them. They should ne'er beryllium composted.

3. Trim iris foliage

Trim the leaves of the rhizomes you person retained utilizing a crisp knife. Doing truthful ensures the plant’s vigor goes to establishing roots alternatively than maintaining leaves. The leaves should beryllium chopped backmost truthful they widen astir 6in (15cm) supra the rhizome. 

Hold each rhizome successful your manus betwixt thumb and forefinger and trim roots that widen past your hand, too. 

4. Replant iris rhizomes

The divided steadfast rhizomes tin beryllium replanted. For each, excavation a spread that tin accommodate some the rhizome and its roots. The plants should beryllium astir 12 to 18in (30 to 46cm) isolated with taller iris varieties further isolated than dwarf versions. 

Bear successful caput that iris rhizomes should not beryllium excessively deep. ‘The rhizome should beryllium placed astatine ungraded aboveground connected dense soils, but a small beneath the aboveground connected airy sandy soils, arsenic they volition enactment their mode backmost to the surface,’ advises The Royal Horticultural Society (opens successful caller tab) (RHS). 

However, it is important to propulsion the rhizomes into the spread truthful they are good bedded in.

Can you disagreement iris anytime?

Plan to divided irises astir six weeks aft they person flowered. This mode they volition turn acceptable for the adjacent play earlier they go dormant for the winter. ‘Avoid dividing during wintertime erstwhile irises are trying to past connected stored vigor successful their rhizomes,’ says Laura Spencer.

How agelong tin iris rhizomes enactment retired of the ground?

Iris rhizomes tin enactment retired of the crushed for a small portion if you aren’t capable to replant them straightaway – oregon you privation to walk them connected to a gardening person oregon relative. ‘It volition not harm the prepared rhizomes to stay retired of the crushed for 2 weeks,’ accidental the experts astatine Michigan State University Extension (opens successful caller tab).