1. Annual weed, these weed die in winter and need seeds to come up every year.
Pre-emergent herbicide don't kill any grass or weed, it only prevent ALL seeds from sprouting. You should spray pre-emergence herbcide every three month from spring to fall in order to stop weed from coming up, because the seed sprout all year except winter. Some weed specifically sprout in the fall and spring pre-emergent herbicite is too late for them.
2. Perennial weed, only wide spectrum herbicide will kill these weeds, but then you will kill your lawn as well. These weeds don't need seed to come back every year, your only option is to hire someone to remove them one by one.
If the weed already came up, you need to use post-emergent herbicide that kills the plants. Of course you don't want to kill grass, so the post-emergence herbicide only kills broad-leave weed (宽叶草），but not all weeds are broad-leave, so post-emergence herbicide cannot kill all weed without killing the grass.
So if you have grassy weed that are perennial, your only option is to hire someone to dig it up. I am talking about crabgrass. It's a headache.
I think you should just keep paying TruGreen. You don't want to deal with this headache.
一直用的TruGreen，每年涨价。每次renew都很头疼，要打电话去讨价还价。
今年涨价太多，我不在乎后院有杂草。
但因为有HOA，前院的杂草必须得除。自己撒除草剂的话，早春什么样的除草剂比较专业有效？谢谢！
Scotts Turf Builder 42.87 lbs. 15,000 sq. ft. Weed and Feed Weed Killer Plus Lawn Fertilizer 25009 - The Home Depot
Weed management is a huge topice.
1. Annual weed, these weed die in winter and need seeds to come up every year.
Pre-emergent herbicide don't kill any grass or weed, it only prevent ALL seeds from sprouting. You should spray pre-emergence herbcide every three month from spring to fall in order to stop weed from coming up, because the seed sprout all year except winter. Some weed specifically sprout in the fall and spring pre-emergent herbicite is too late for them.
2. Perennial weed, only wide spectrum herbicide will kill these weeds, but then you will kill your lawn as well. These weeds don't need seed to come back every year, your only option is to hire someone to remove them one by one.
If the weed already came up, you need to use post-emergent herbicide that kills the plants. Of course you don't want to kill grass, so the post-emergence herbicide only kills broad-leave weed (宽叶草），but not all weeds are broad-leave, so post-emergence herbicide cannot kill all weed without killing the grass.
So if you have grassy weed that are perennial, your only option is to hire someone to dig it up. I am talking about crabgrass. It's a headache.
I think you should just keep paying TruGreen. You don't want to deal with this headache.
有专门应季的除草剂，就太好了。
今年准备先在一个地方试试看。效果好的话，以后全部自己弄，应该不难
想先自己试试看，不行再换其他的除草公司。感觉TruGreen除草效果似乎不如其他小公司。
真喜欢没有HOA的房子，不管家草野草只要不疯长按时割，就没人管。对环境也少了很多污染。
除草防草的东西有很多种。关键是要掌握时机。早了白撒，晚了白忙。其实前院就是不除草，只要及时割草，HOA也说不出什么来。
1： 防杂草主要防种子繁殖的杂草。早春的除草剂应该主要针对pre-emergent weed, 基本可以全年使用。
以前读书时，一个老美教授说他自己做杂草防治最有效的办法是：早春深割草，露出草根，并且割下来的草都收集起来扔掉。
我猜他大概是想尽量把杂草种子处理掉
2： 夏秋喷洒的除草剂就应该针对post-emergent weed，以及治宽叶杂草的。
宽叶杂草有药治。
跟草坪类似的杂草，要靠人工拔。既然跟草坪类似，不拔的话也应该看不出差别？
我以前除草公司的单子留了不少。准备依葫芦画瓢，每年也撒5-7次除草剂
crabgrass最难看，因为是趴着地长，割草后也能看出来。其他细叶野草可能还是能看出来的。我有的邻居草地就是好，又密又单一，我的草地也就是在挣扎吧。
草本植物就是没有茎的植物。在热带或者加州所有的草本植物都是多年生的，因为没有冬天。草本植物到了温带和寒带就有了区分，有的植物能够过冬，有的植物到冬天死掉，就是annual。实际上一个种里面的草都有不同的变种，有的可以过冬有的不能过冬。所以多年生和一年生的草本植物要看你在哪里。
过冬的草一般根系比较发达，这样地上死了地下的根还是活的。很多草本植物的花是一年生，因为大多数精力花在开花上，没有营养多长根。
网上搜了一下，很难确定是哪种草。
附近LOWES店里有Centipede 和 Kentucky 草籽卖。我们这里的草坪基本都是这种夏容冬枯的草，我的估计也是这种。
还有一种四季常绿的草长得也差不多，但叶子更肥厚。有点像你家的St. Augustine
我用过TrueGeen效果很差，整得邻里中杂草最多是我。公司都是一户一户按排班的时间表来，等轮到我，有些杂草已经结籽。只好自己来。最重要的是开花前除一次，自己看，主要是在早春和早秋。夏天还会再次开花。
我这一条街也只有我家还坚持在用Trugreen。
每年早春邻居家草坪还都没返青时（也许已经用了药），我家草坪就已经有不少绿色杂草了。
今天只renew了自家的草坪除草。
出租房等过了年，再考虑是换一家除草公司，还是试着自己弄