Late Spring 2025

Spring has already sprung, and we are . . . sproinging (?!) headlong into early summer very soon in SoCal! Last week's daytime high temperatures (late April) were in the 60s, but next week's (mid May) are in the 80s! Perhaps more importantly for tropical bonsai, nighttime temperatures have pretty much stopped going below the key 50F mark. Read on to find out what that means for the trees, and what work I'm focused on this time of year.

Tropical Bonsai: (note: I keep tropical bonsai outdoors year-round in our Mediterranean Climate, and they are subject to more cold than they might naturally like. If you are in a more tropical climate, or have a greenhouse, your mileage will vary). Genera like Ficus and Bougainvillea begin growing more consistently now, and I can safely cut back their "winter coat" to set them up for success this summer. By "winter coat" I mean that I tend to let these trees get a bit shaggy and overgrown as fall winds down into winter, ensuring that any cold damage to growing tips will be outside of my desired silhouette. Now, I will remove that long leggy foliage so that my first round of vigorous warm-weather growth is closer in to the trunk. What I really don't want is for my first big explosion of growth to happen way out on those leggy tips, and then I have to cut it all off later -- what a waste. I won't completely defoliate any tropicals yet, but I will cut them back hard as I start to see signs of new growth. Because that first flush will be fairly vigorous, I will then cut it again pretty quickly (maybe once it has extended 3-4 new nodes). This will help prevent the long internodes common to rapid growth at the beginning of the season.

Repotting: For me, it's still to early to repot tropicals, and it's pretty much too late to repot temperate deciduous species (I try to catch them as the spring buds are just opening, and most of mine are in full leaf by now). If I do have to repot a deciduous tree this late in the season, I will do a hard cutback to limit its foliage load, kind of resetting its spring. I am still repotting some healthy vigorous junipers, as long as I have a couple of days of cool and overcast weather, but I probably wouldn't do it on those upcoming 80-degree days. Good aftercare makes a huge difference with repotting, so if you have a nice shade house, misting system, etc., you can probably get away with extending your repotting into warmer weather. I will also be repotting Mediterranean species such as Olives and Pomegranates this time of year (trimming any new growth back beforehand, to avoid wilting). Trees repotted Now will definitely benefit from two weeks of shade to recover.

Fertilizing: Do it!! If you haven't started fertilizing already, you really should. I especially fertilize my pines heavily this time of year, since they won't get any fertilizer after decandling mid-summer. For my bonsai in inorganic soil mixes, I like a slow release organic fertilizer with single-digit N-P-K values. For pre-bonsai and raw stock in large pots and organic soil mixes, anything handy is fine, including soluble chemical fertilizers - just follow the directions!

Temperate Deciduous Bonsai: I've already cut extending new growth on Maples ad Crape Myrtles at least a couple of times, and that will continue now with any shoots that extend beyond 4-6 nodes as they arise.

There is a lot more going on this time of year, but this a quick look at some of the more timing-critical work I am doing. Happy Spring, and Happy Growing!