No real secret to growing the easiest hybrids with Anigozanthus flavidus parentage, but they do prefer both good drainage and regular warm season irrigation. In habitat they even well tolerate seasonal winter flooding and summer wild fires. Full sun, good air circulation, planting out in cooler months to minimize drought stress,(typical nursery container mixes for them very quickly dry out if you aren't adequately wetting the root ball, and probably accounts for most plant deaths). They are extremely easy once established, but don't crowd the foliage or insist on overhead spray irrigation which encourages ink spot disease.

A 5 gallon nursery can with crammed roots in a south facing spot and only getting handwatered twice a week; you killed it from lack of water, plain and simple. I agree that Kangaroo Paws can be temperamental to grow with regard to drainage and proper watering, but the Anigozanthus flavidus cultivars are among the easiest to grow. Do amend the soils for good drainage, give it full sun and good air circulation and avoid overhead spray on the foliage if you want to minimize the Ink Spot disease, and regularly prune off infected foliage to the ground, especially if it isn't getting full sun and/or good air circulation. I have found that some species/cultivars of Anigozanthus are much more tolerant of clay soils than others, and any of the A. flavidus cultivars are fairly tolerant of clay, as well as it is sloped or amended slightly so that it doesn't stay saturated. Not a good candidate for planting where it gets constant overhead spray irrigation which in combination with too little full sun can lead to the fungal disease. While this plant is rather drought tolerant in the ground once it is established, as a container plant in its original size container from the nursery, twice a week watering in full hot sun just isn't enough, and you cooked it. Get another one now that it has cooled down, get it into the ground in full sun with good drainage, and the twice a week watering regimen will probably work just fine. If you prefer to keep it in a container, buy a smaller one gallon, repot into a larger 5 gallon container, and hook it up to an automatic drip irrigation system so that it gets a little bit every or every other day, or keep an eye on the plant so that it doesn't ever go bone dry between waterings.

First of all, you might want to start posting on the CA gardening forum. There are quite a few SoCal gardeners on it. Second, soil and prep are ALWAYS more important than plants. If you have clay soil it won't drain well and watering so often will create root rot. Yes, new plants need to be watered to establish themselves - so it's a fine line between "watering enough" and "drowning", in this case. Your calla lilies will yellow and go away very soon. They HATE hot soil. They are partial shade plants at best, especially in your area. In coastal CA they bloom around Nov/Dec thru mid-May. "Hercules" gets not only very tall but will grow outwards at a steady rate. I wasn't successful with my own Anigozanthosos (kangaroo paw), but when advice says to prune back after flower, they mean the flower STEM, not the whole plant including leaves. Sage can be pruned almost any time, as far as I can tell. But like rosemary, you want to avoid cutting into the woody stems. Cut it back to a pair of leaves - any pair, just so you don't leave it leafless on that stem. Bougainvillea can be touchy about getting established. They hate being transplanted and it's very easy to harm the rootball because it falls apart easily. Once it's adjusted, you can cut back the watering gradually. "Sulking" won't harm it as long as you water as soon as you see the symptoms of leaf curling, etc. Dahlias are prone to root rot, especially when dormant in winter. With your clay soil you might be better off growing them in pots if you refuse to amend your soil. Watering too often and shallowly is a common error for beginners. Most plants prefer watering less often and deeply, and from underneath rather than above. Good luck!

Hello from Australia! I own and run a retail nursery supplying many plants including anigozanthos (our beautiful kangaroo paws). They require absolutely perfect drainage to thrive, never leave them sitting in water. Water with a can is fine, avoid splashing the plant too much as they are prone to a fungal disease similar to 'black spot' which is incurable. You may not have this problem in the USA. Air circulation and not crowding them too much is important for the same reason. If you want your 'paw' in a permanent pot, I would choose one 12inches wide or larger. They will keep clumping and multiplying and form a spectacular display with lots of flower heads. Watch out for high phosphorous ferts as they can sometimes burn, I use blood and bone only on my sensitive Aus. natives. Good luck!