Check Out This Article in the Autumn Water Garden Journal

Collective Wisdom Tips for Growing N. ‘Detective Erika’ (or Any Hardy ISGs)
Excerpt from the IWGS Journal, Autumn 2023, Vol. 38-3
By David Curtright

[The articles featured in this column and in future Journal issues have been gathered from the collective wisdom freely shared on the IWGS Facebook page. Our goal is to ensure that these types of discussions can continue to be accessed by the waterlily collective as a whole.]
On September 12 of this year, a post was made by Peter Nitzsche concerning the non-performance of his specimen of N. ‘Detective Erika’ that elicited quite a response from our group participants. His complaint was that his plant had not awakened completely this season despite having been treated in the same manner as he always had used, and despite other plants in his collection having done well this season. His question was, in a word, ‘why?’
The answers came fast and furious, with some about what soil had been used, whether he had marauding plant molesters in the pond, you know, koi, turtles, etc. He didn’t. He was asked about water depth, temperatures, etc. His answers made us aware that he had not committed any of the usual sins that many neophytes do, and Justin Titus came to his rescue early on by saying that he is an experienced grower and that our advice should reflect that. It was then that the conversation got real.
Mike Giles, no stranger to growing ISGs, said that it will depend upon which variety one has, and that while he does not keep ‘Detective Erika’, and so has no direct experience with it, it should be borne in mind that being half-tropical, some ISGs will be sensitive to abuses such as leaves being eaten off, overcrowding, etc., and that they will go down if it gets too bad. He suggested correcting any of this and that the plant should recover. He then mentioned that Jacklyn Rodman, in the Los Angeles area, had reported problems with the primary growing point on the rhizomes of this variety frequently rotting away during their dormancy, and that she had had to rely on the side shoots to carry the plant through into a new season. This problem was later reported by others.
Tamara Kilbane wondered if Mr. Nitzsche had tried to grow it in water that is too deep, mentioning that ‘Detective Erika’ is one of the hardiest of her ISGs, but that it is among the last to start growing in Denver, and that she was in the habit of raising it to shallow water, then lowering it as it grew.
Tom Gleeson mentioned that he had noticed that he had to repot them each year because they seem to be greedy feeders, and that they will languish if left to their own devices while being trapped in a pot.
Kelly Billing, ever a font of good information, spoke about her experience with ‘Detective Erika’, saying that it is hardiest of her ISGs, and that, contrary to Tamara Kilbane’s experience, it comes up before some true hardies. She spoke about how temperature shocks can cause plants to go into a false dormancy for a season, or for part of the season, but that they usually do well in subsequent seasons. She said that she had experienced this phenomenon during a cold snap early this summer.
Leo Poldini chimed in with his experience with ‘Detective Erika’ and other ISGs, saying that he had done several things involving fertilizers, water depth, and soil types to see what will work for him, but that, try as he might, ISGs did not perform well for him, in some cases being more difficult to grow than tropicals. He lamented not having clay to include with his soil. He echoed the problem originally cited, that of the primary growing point rotting away during dormancy.
Others supplied their own advice, which was much the same as what had come before. The salient points to take from this discussion were that ISGs, and perhaps ‘Detective Erika’ in particular, need to be well-fed, need to be divided each year, are best started in shallow water to get them going in the spring, and that they should be lowered as they grow for a good showing.
My own experience with ISGs has been mixed, but ‘Detective Erika’ is one of my more successful waterlilies of any type. I do have to repot them seasonally, but they never really go dormant in my climate, so I can repot them from late February to mid-September for nearly year-round growth. They do not like surface competition, and while I have not had the primary growing point simply rot away, the plants do require annual repotting. As a group, the ISGs have not been a smashing success for me, but they are beautiful in most cases, and with more varieties being introduced each year, and with fora such as this to exchange data, we should all have a good time with them well into the future.
About the Author: David Curtright is the owner of Freshwater Gardens, Inc., Escondido, California, USA. He is the president of the Southern California Water Garden Society and is locally recognized as an expert in the field. He can be reached by email at