Is water hawthorn a genuine 'hardy' plant?

[Joshaeus]

Hi everyone! Earlier today I did some research about the climate in the portions of South Africa where Aponogeton distachyos, water hawthorn, is native. What I found made me give some thought as to how we generally keep this plant in ponds...for Cape Town, South Africa, for example, the monthly average low temperatures seldom dip below the low 50's fahrenheit; Weather Spark observes that "Over the course of the year, the temperature typically varies from 48°F to 76°F and is rarely below 41°F or above 84°F." The logical inference is that in much of its native range, water hawthorn almost never encounters even a light freeze and thus spends the winter actively growing.

Here, then, is my question...since water hawthorn do not usually encounter any significant amount of freezing weather in their native habitats, should we really treat them as a 'hardy' plant that can be left outside during harsh winters? My thought is that since water hawthorn - unlike most water lilies - also goes dormant during warm weather, leaving them to go dormant during a freezing winter would result in the hawthorn going dormant twice a year for several months each time in many areas, and I suspect they would not be able to replenish their bulbs enough during their relatively short growing periods to avoid burning out after only a few years at most. It seems to me that they should probably be grown indoors during the winter (likely an easy task, as many other Aponogetons are common aquarium plants...in fact, I have seen A. distachyos offered as an aquarium plant) and put outside as soon as the water is going to stay liquid. Thanks

(PS...if this is right, this would also explain why Aponogeton distachyos rarely becomes invasive outside of warm climates like California).

 

[j.w]

I had it once and it did great for awhile, even sent out little floating babies. Well I should have collected those little babies and planted them cuz one year the mother plants just disappeared after having it for several years. Seems to be kinda picky here at least in my pond.

 

[Joshaeus]

I had it once and it did great for awhile, even sent out little floating babies. Well I should have collected those little babies and planted them cuz one year the mother plants just disappeared after having it for several years. Seems to be kinda picky here at least in my pond.

When I look water hawthorn up, lots of people give similar reports of the plant doing well for several years and then simply disappearing. That is part of what prompted me to ask this question...

 

[addy1]

I have one sort of limping along, will see if it comes back next fall/spring

 

[Lisak1]

I've never been able to get it to come back, even though it's listed as zone 5 hardy.

 

[GBBUDD]

It did not come back for me "which is not a bad thing as it right now is growing like ten weeds . by the time i get home i am betting i will have 3 - 55 gallon barrels full. and i only purchased a handful at the begining of the season. I also introduced some tetras and some torpedo barbs . i will try to catch as many as i can but the winter will be population control

 

[Jhn]

Mine does ok but not great. Have some in two of my ponds. The one is about 7 years old. The other is about 3 years old. The younger one has spread some to the lily pots, but not much.

At my old house I had some it did really well, it was growing out of all the underwater pots in the pond. The only difference is that pond received much less sun, than my current one.

 

[Joshaeus]

Mine does ok but not great. Have some in two of my ponds. The one is about 7 years old. The other is about 3 years old. The younger one has spread some to the lily pots, but not much.

At my old house I had some it did really well, it was growing out of all the underwater pots in the pond. The only difference is that pond received much less sun, than my current one.

Here's a thought...did it ever go dormant at your old house? The shady pond was probably cooler than your current ones, and if it was cool enough (no warmer than the low 70's where the water hawthorn bulb was) the plant could have never gone dormant in summer (or, at worst, only briefly) and thus would have only had to deal with a winter dormancy. If water hawthorn is instead going dormant twice a year - once in summer (when the water is too warm) and once in winter - it would probably not do as well because the plant has to spend half of the year starving, with only a few good months between each dormancy period. (PS...how much sun did the old pond get?)

 

[Jhn]

@Joshaeus The old pond probably got about 6 hours of sun, the mother plants so to speak would go dormant in the summer. The smaller ones would just grow all summer.

The old pond still got warm though, never checked the temps to say how warm. My current pond although twice the size gets sun all day long...

 

[EricV]

I've never been able to get it to come back, even though it's listed as zone 5 hardy.

It comes back for me every year (4 now) and IIRC I am 20 miles south of you. I started with 3, now I have 4. One must have seeded. Mine doesn't really go dormant in summer either; it might slow down a little.

Certainly they are not as vigorous of growers for me as my lilies are.