Rooting arrowheads

by Steven Tay
(Singapore)

Hi, I have tried to grow arrowheads once a year when they become available here (Singapore) during chinese new year. Not being superstitious, just love the green leaves. However, the tips of the leaves as well as necks of those I grow tend to burn, turn brown and I have to dispose of them. I grow them on pebbles of about 5mm and filled water up to rim, above the tubers & roots. I've tried with & without sunlight and placing them in absence of strong wind.

Doug says - interesting problem. Here they are common roadside / native plants and not a problem. Crisp brown tips indicate plant water uptake stress. Either losing too much or not getting enough. "burning" or rotting could be any number of things.

Is the water chlorinated? With chloramine rather than chlorine? In either case, you're going to have to get rid of the chlorination as this can be one leaf tip problem.

Water depth is another potential issue. You're buying a plant that's already rooted/leafed out I assume so you're going to have to plant it at the same depth and there should be a water line on the plant. Here we simply put the roots slightly under the soil (we use clay soils rather than pebbles but small pebbles should work for rooting - not maintenance) and watch it grow.

This is a hardy temperate zone plant - if you're talking about the N.A. native and high heat/humidity isn't going to be appreciated in early cultivation. I also don't know whether there's a dormancy issue here - that the plant isn't going to survive because it has been dug up here before going into dormancy or too early in dormancy and it is going to waste away without that winter sleep. (typical of many plants from northern zones under forcing)

If I was guessing (and I am) I'd look at water quality first. Then I'd want to keep the plant cool and semi-shade until it started growing new leaves. And hope the dormancy issue isn't the problem.

Sorry - growing these great N.A. natives in tropical climates as a houseplant is something I've never done.