I'm going to take an entirely different approach. And this is based on many years as both a professional design/landscape consultant and garden coach. Extensive perennial plantings are high maintenance. Not sure how large your assorted perennial beds are but maintaining 8 of them, 3 of which are very visible, is going to take a lot of time. Based on your screen name, I assume you work for a living? And no doubt, so does your spouse. Do you want to spend limited free time doing a lot of gardening or would you rather have more time to just enjoy your outdoor space? And if you are new to gardening, there is a high learning curve involved with an extensive, existing garden, I'd suggest that you slowly convert the perennial beds to lower maintenance plantings, focusing on small trees and shrubs. These will not be maintenance-free but will require less attention than a heavily herbaceous perennial bed. You can certainly keep whatever perennials you find very appealing, but include them as only a portion of the plant selection, not the focus. There is a horticultural rule of thumb - the larger and longer lived a plant, the less ongoing maintenance it will require......a sliding scale with annuals and perennials at the high end and shrubs and trees at the lower end. Also, the more evergreen, the less maintenance required (generally). You may want to hire someone to help with this. Garden coaching/consultation is a pretty active business segment in many parts of the country. They can help you both identify the plants you have, determine which might be appropriate to keep and help to select others to replace and offer lower maintenance and a longer season of interest. At a modest hourly rate, this may be an excellent investment. FWIW, most Master Gardener organizations do not provide for this type of onsite, individual/personal attention, at least under the auspices of the program. Their mission is community outreach via plant clinics, community gardens, answer lines, etc., not a one-on-one approach. Checking with your local program office or county extension should clarify.

I think it is probably lack of water or temps. I am leaning towards temps, just because you said they were ventricosa and they are the sherman tanks of nepenthes. The brown spots look to originate from the veins which seems to tell me that the issue is from within and not an external attack. Ventricosa is technically a highland nepenthes. Although it will grow like a weed in most any condition. That tells me that humidity is probably not the issue since I grow mine if lower humidity. The next possibility is tempurature. You are in zone 9, how cold does it get there during the winter? Most neps, with the exception of a very few (2 that I know of khasiana and lamii [i think]) can withstand temps below 45. I had a ventrata burn at the growth points this fall when temps got below 50. It is doing fine now and started to branch and vine as a result, but I was nervous for a few weeks. (I haven't lost a nep yet.) Ventricosa if a very forgiving plant when it comes to water and light, but you should never let a nep dry out. Which judging by your experience, I am guessing is not the issue. That is what keeps leading me to tempurature. If that is the case, I think as long as you give them attention and get back to optimal conditions, they should bounce back. Leaves may die, but as long as new growth appears, then you should be ok. In it's weakened state try not to overwater. If leaves are dying, this is food for fungus now all it needs is a nice drink. If it is lack of water, then you should be fine too. Just make sure not to water log it for the same reasons as just mentioned. A little more light may help during the healing phase if the pitchers weren't already a reddish color before this problem. Otherwise, light is just right. Hope this helps...

yellowing around the edges.. moving toward the center.. starting on the oldest leaves.. the first out in spring is classic signs of insufficient water.. period ... i know some nurseries.. that water 3 times a day ... a picture would confirm such no clue where you are ... so all the above is speculation... hotter the zone.. the more the issue become lack of water ... the hosta is basically sacrificing the oldest leaves. in an attempt to retain as much water as it can.. to protect the plant itself... if all the leaves yellow and brown.. you will have achieved what is called summer dormancy.. which is caused by.. LACK OF WATER ... the biggest problem is that now is the time that hosta are growing new roots.. and storing energy for next spring.. and instead yours are shutting down ... they will not be much bigger next year.. if the issue isnt solved.. ken

The carnivorous plant forum should be able to give you better info than here.