I know this is old, but after reading the comments I had to interject. Treat it just like you would a wound on a human... Step 1: Assess the damage without touching, and probably causing further damage. Determine weather you want to attempt to repair the plant, reroot the severed piece for planting later while trying to nurse the original until the wound heals, or say "Adios" by asking yourself a few questions. What happened? What caused this to happen? Where is the primary damage located? is there secondary damage? With my help can this plant heal or is it a total loss (you'd be surprised what plants can survive!)? Is it worth saving or do I have tons of this plants and the time spent caring for it will be better spent caring for the other plants? Try to save it because you love that plant, it was fruit laden and you can't bear to lose all that delicious fruit of your hard work, and/or you just want to know how & that you can?! Great! Step 2: clean and sterilize the wound and any thing you will use in this plants repair or face the very likely possibility that the plant you're about to work so hard to save will look like it's getting better (because it will be due to your quick action in saving it) until the disease/virus it contracted via the open wound that was exposed to the soil and air for however long didn't get cleaned and sterilized when you used your grubby garden fingers to perform plant surgery and then used an old mildewy roll of duct tape you found in a cardboard box on the side of your house... It could be totally fine, too. I just know I would prefer my surgeon to use sterile tools when reattaching me when I split open. Step 3: Visualize what needs to be done in order to not injur the plant again or to cause the damage to get worse or split further. sometimes if it's a vertical split down the length of the plants main stem I'll use some large gauge natural fiber twine (⅛" jute) to wrap snuggly around the stem below the split until I've come just past where the split starts and then tie it off or secure so that the knot or securing is easily undone when you're ready to splint. This way it protects the split from growing or getting worse as you start to handle the plant. Step 4: Get everything you need to make the repair. This is kind of up to you because every repair will be different. A splint is likely what you'll need to make but not always and size will vary according to your plant and scale of the injury. You can make splints out of tons of things lying around the house. firm backing for the splint pieces and something to hold them together on either side of the split is all there is to it. This could be popsicle sticks and tape or bamboo garden stakes and rope/bungee cords. I've even used routed out 2x4's and C clamps to fix a badly damaged fig tree grown from my father's ashes. You'll also likely need support to take tension off of the pieces that split so that they can properly heal. if you don't do this then it will never heal correctly or take too long to heal causing the rest of the plant to suffer because it's putting all of its energy into healing this wound that pulls open a little with ever passing breeze. Step 5: With adequate support in place or within arms reach, carefully right the plant so that the two halves or the split are in line with each other and in the position the plant will remain in during it's healing and growth. Once achieved temporarily support the plant in this position with a cage & ties, several stakes & clips, or even with twine from an over head boom like a nearby trellis or a sturdy structure you can anchor the plant to from above to hold it in place while you work. Step 6: if time has passed or you might have contaminated the wound, you can clean again now that it's been moved around and possibly opened further. I use lukewarm h²O, Dr Bronners Original Castille (dark blue label & smells like peppermint), and h²O² (Hydrogen Peroxide 3%) at a ratio of USE AT OWN RISK! ALWAYS TEST NEW DIY SPRAYS BEFORE MASS USE! 1T Doc Bronners 8T h²O² (Hydrogen Peroxide) 1 gal h²O (distilled) If you don't want to use this or can't because it's a sensitive plant species then just take some clean water and spray the wound to help flush the site from debris or surface disease. Step 7: Bring the split in line together and splint, making sure to try and fit the break back together like a puzzle. the closer the match the easier and faster the heal. Once the splint is in place snuggly wrap with clean dry paper towel or piece of cloth (Ace bandage works well too). Secure the wrapping and splint with tape or twine or any other means. Step 8: Reposition or make more permanent your support system. ensuring that the plant is fully supported with no weight or tension on the injury point OR any other weak points that the weight distribution and new support contact points may have created. Step 9 (optional): I do this sometimes but not Everytime. If the plant was injured due to some kind of environmental or nutritional stressor (too hot, too wet, nutrient sufficiency etc.) I try to give the plant a little boost regarding that issue. a drink of water (not too much) & some food to fuel it for it's recovery. Not too much because it can shock it or cause further issues. I usually use some liquid fish emulsion & water to feed and water at the same time. I also sprinkle pure ground cinnamon over the wound & wound area after the repair plus around the base of the plant and soil below the plants canopy. Cinnamon has antifungal properties and is also used as a rooting hormone. it keeps the site dry and free from fungus and disease spread, pests generally tend to steer clear of it and it seemingly helps the plant regenerate it's cells more quickly (unproven but it works for me). This is my best advice. It comes from a person who feels the internet lacks truth, substance, detail, and alternative options that explain why they do it that way. I've also had lots of success doing it this way. You may or may not too.

Hi' was the leaves still on the plant when buried it, you need to take the leaves off the part you are going to stick in the ground. But' all tomatoe plants have suckers, look between the leaves and the stem' there should be a little tomatoe plant growing - snap it off and plant it but make sure you keep it water good and I have taken a plant that was broken and put it in a bucket of water and put it the shade until it grew roots and then plant it. Good luck - Spider

I dig a trench about 3 inches deep if that will accommodate the root ball or just enlarge the end where you are putting the root ball and lay the rest of the stem in the trench and cover with soil. Of course you can dig the trench deeper if you'd like but at least 3in deep. The top of the plant should not be covered, of course, and I prop up the top with a small nursery pot until it starts growing, usually a week or so. I got a great deal on a bull's heart which was pot bound in a tiny pot and so leggy and tall the stem could not support it, I planted it as I described and it is now healthy and has several beautiful tomatoes on it, not yet ripe. You do have to be careful where you dig after you plant a tomato this way and I water this tomato differently then my others, making sure I water over the whole stem area. I always mark the area with something to remind me where the stem is to I don't forget and dig a hole and ruin the tomato. Yeah, it is a good technique for the really tall and spindly tomatoes.

Looking more into this, I think it may actually be voles, not gophers. So thank you, gorbelly, for the advice about foil. Do you just mean wrap some foil around the base of the stem? I have 2 surviving tomato plants. One is about 3 ft tall and the other is a lot shorter. This morning, I noticed the shorter one was wilting even though I'd given it a good watering yesterday. I was worried it had been attacked but couldn't see any damage above the soil. I transplanted it into a pot, trying to keep the root ball in tact (I may have damaged some of the extended roots, though). It look s pretty sad right now but I'm hoping it'll survive. Here's the 3-footer still looking healthy, but I'm worried! Aside from the foil, what's the best vole deterrent, if that's what it is? I've read some stuff online and people are saying castor oil is a good one, although I'm still unclear as to how exactly I apply it. I see no entrance holes anywhere in the surrounding dirt. People are saying sonic repellents don't work that well. I may not be able to get to the store until tomorrow, so I'm hoping it doesn't get attacked by then. I'll add the foil in the mean time. In a super desperate move, I took the remains of the first detached tomato plant and tried to bury it as deeply as I cold in another area of the yard, right next to some onions and kale. I know I'm totally dreaming this will work out but I figured it was worth a try. I know it would be an admission of defeat but I'm still considering moving the zucchini and cucumber, which are still relatively small. I just feel like I need to do something ASAP and not wait around until I figure out the deterrent option.