International Aroid Society

Dear Aroiders,

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I know that this question is not aroid specific but I know no other forums where I could ask it (and it incudes aroids).

Does anybody know what physiological difference might cause leaf tip in some aroids, but not in others? I have some Philodendrons, a Dieffenbachia cultivar, two different Syngoniums, a Spathiphyllum cultivar, Epipremnum aureum, an Aglaonema and Monstera deliciosa (I had another Monstera with small leaves, but it has died). Of these genera, Monstera, Spathiphyllum and Epipremnum aureum shows leaf tip burn (the tip of the leaves becomes necrotic) followed by necrosis of the whole leaf. Monstera deliciosa is a hard plant to kill, but here in my appartment it can not develop normally, the leaves become necrotic. It applies to Epipremnum aureum, another easy houseplant too. The same might be the situation with Spathiphyllum, but I bought it recently and I mainly watered it with deionized water. Lately I gave it tap water and it started to exhibit leaf tip burn too. I had another Monstera which has perished after necrosis of all of its leaves. On the other hand my Philodendrons, Dieffenbachia, Aglaonema and Syngoniums are not affected at all.

In my aquarium I had Anubias plants which suffered from nercosis of their leaves too. They perished (I used 1:1 mixture of tap water and deionized water).

My non-aroid plants suffering from leaf tip burn include Dracaenea fragrans (necrosis is limited to leaf tips) and Chlorophytums. I have Chlorophytum comosum (again a plant nearly impossible to kill) and a Chlorophytum orchidastrum cultivar (=E2=80=99fireflash=E2=80=99). Both suffer of severe necrosis and loose all of their leaves and die when watered with tap water. When I water Chlorophytum with deionized water (once a month or so with citric acid dissolved in it to lower pH) my Chlorophytums do much better. It is interesting as I read that Chlorophytum comosum is sensitive to fluoride and raising the pH of the water (that is the opposite what I do) helps by decreasing solubility of fluoride ions.

My non-aroids not affected include a Vriesea cultivar (I know that bromeliads should not be watered with tap water but recently I started to do so with no problems) and a Schefflera.

Th pH of our tap water is around 8.0 and that of deionized water is around 5.5. Light levels are low but Monstera deliciosa must not die where Philodenrdons live and grow.

The plants do not suffer from a =E2=80=9Ebad gardener=E2=80=9D as at my workplace my Mosteras florished. There lives the motherplant of my M. deliciosa and it is huge, without any leafburns and the small leafed species (which I lost here at home) grew well without any blackening of the leaves too. Sunburn, under- or overwatering, too heavy soil mix should be excluded (maybe it is not the right word... I mean, do not consider them).

Maybe it is not the water, but I can not think of anything else. Monstera deliciosa and Chlorophytum comosum are so easy plants to grow and make thrive that it is really strange that I can not even keep them alive here at home.=C2=A0

Do you have any idea?

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Ferenc